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Latest Red Hat advisories
Medium [CVE-2026-68205] Fix subdev owner overwritten in v4l2_async_register_subdev_sensor
In the Linux kernel, the following vulnerability has been resolved: media: v4l2-fwnode: Fix subdev owner overwritten in v4l2_async_register_subdev_sensor() The v4l2 helper v4l2_async_register_subdev_sensor() calls v4l2_async_register_subdev(), which is a macro that expands to __v4l2_async_register_subdev(sd,THIS_MODULE). Since the macro is expanded inside v4l2-fwnode.c, THIS_MODULE resolves to the v4l2-fwnode module rather than the sensor driver module that originally set sd->owner. This causes the problem that the sensor module's reference count is never incremented during async registration, so the module can be removed while the subdevice is still in use by a notifier (e.g., a CSI-2 receiver bridge driver). Fix this by renaming v4l2_async_register_subdev_sensor() to __v4l2_async_register_subdev_sensor() with an added explicit module argument and introducing a wrapper macro: #define v4l2_async_register_subdev_sensor(sd) \ __v4l2_async_register_subdev_sensor(sd, THIS_MODULE) This ensures the sensor driver module is properly referenced even when the sensor driver does not init the owner field before calling v4l2_async_register_subdev_sensor() and prevents premature module removal. The `v4l2-fwnode` module, responsible for video device node management, incorrectly handles module ownership during asynchronous subdevice registration.
Medium [CVE-2026-68204] check for vb2_is_busy when toggling caps
In the Linux kernel, the following vulnerability has been resolved: media: vivid: check for vb2_is_busy() when toggling caps The vivid_update_format_cap/out() functions must only be called if the capture/output queue are not busy. But for the controls that select the CROP/COMPOSE/SCALE capability that is not checked. Only when streaming starts will they be set to 'grabbed' and it is impossible to change the control, but between REQBUFS and STREAMON you are still allowed to set these controls. Since vivid_update_format_cap/out will change the format, this can cause unexpected results. Besides adding these checks, also add a WARN_ON in vivid_update_format_cap/out() if the queue is busy. I'm 90% certain that this is the cause of this syzbot bug: But since we never have reproducers, it is hard to be certain. In any case, these checks are needed regardless. A flaw was found in the Linux kernel's media subsystem, specifically within the vivid driver. The vivid_update_format_cap/out() functions, which handle video format changes, can be called when the video buffer queue is actively processing data. This occurs because checks for a busy queue are missing when certain capabilities are toggled between the buffer request and streaming start phases. Affected product named by the advisory: Red Hat OpenShift Container Platform 4.
Medium [CVE-2026-68196] validate assoc response length before subtracting header
In the Linux kernel, the following vulnerability has been resolved: wifi: wilc1000: validate assoc response length before subtracting header wilc_parse_assoc_resp_info() computes the trailing IE length as ies_len = buffer_len - sizeof(*res); without first checking that buffer_len is at least sizeof(struct wilc_assoc_resp) (6 bytes). buffer_len is the length reported for a received association response (host_int_parse_assoc_resp_info() passes hif_drv->assoc_resp / assoc_resp_info_len straight in) and must be validated before the driver accesses the fixed header. For a frame shorter than the 6-byte fixed header, the subtraction wraps. For a four-byte response the result is truncated to a u16 ies_len of 65534, so kmemdup() then attempts to copy 65534 bytes starting at buffer + sizeof(*res), beyond the valid association-response data (CWE-125). A response shorter than four bytes can also cause an out-of-bounds read of res->status_code at offsets 2 and 3. Reject frames too short to hold the fixed header before touching the header or computing ies_len. Also set the connection status to a failure on this path: the caller falls through to a "conn_info->status == WLAN_STATUS_SUCCESS" check after the parser returns, so leaving the status untouched could let a malformed short response be treated as a successful association.
Medium [CVE-2026-68194] drop TXRX_NOTIFY on non-mmio buses
In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7921: drop TXRX_NOTIFY on non-mmio buses PKT_TYPE_TXRX_NOTIFY is an mmio-only event, but mt7921_rx_check() and mt7921_queue_rx_skb() dispatch it to mt7921_mac_tx_free() on every bus. mt7921_mac_tx_free() cleans the DMA tx queues with mt76_queue_tx_cleanup(), which calls queue_ops->tx_cleanup(). Only the mmio queue ops implement that callback; on USB and SDIO it is NULL, so a TXRX_NOTIFY there calls a NULL pointer in the RX worker: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:0x0 Call Trace: mt7921_mac_tx_free+0x64/0x310 [mt7921_common] mt7921_rx_check+0x5f/0xf0 [mt7921_common] mt76u_rx_worker+0x1b9/0x620 [mt76_usb] Drop the event on non-mmio buses via mt76_is_mmio(), as in commit 5683e1488aa9 ("wifi: mt76: connac: do not check WED status for non-mmio devices"). This can lead to a kernel NULL pointer dereference, causing a system crash and resulting in a Denial of Service (DoS). This issue affects MediaTek mt7921 on non-MMIO buses (USB). MMIO-only TXRX_NOTIFY dispatched to tx_free on USB path. Systems without mt7921 USB Wi-Fi are not affected. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-476. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9.
Medium [CVE-2026-68193] drop TXRX_NOTIFY on non-mmio buses
In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7925: drop TXRX_NOTIFY on non-mmio buses PKT_TYPE_TXRX_NOTIFY is an mmio-only event, but mt7925_rx_check() and mt7925_queue_rx_skb() dispatch it to mt7925_mac_tx_free() on every bus. mt7925_mac_tx_free() cleans the DMA tx queues with mt76_queue_tx_cleanup(), which calls queue_ops->tx_cleanup(). Only the mmio queue ops implement that callback; on USB it is NULL, so a TXRX_NOTIFY there calls a NULL pointer in the RX worker: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:0x0 Call Trace: mt7925_mac_tx_free+0x58/0x350 [mt7925_common] mt7925_rx_check+0xe2/0x130 [mt7925_common] mt76u_rx_worker+0x1b9/0x620 [mt76_usb] Drop the event on non-mmio buses via mt76_is_mmio(), as in commit 5683e1488aa9 ("wifi: mt76: connac: do not check WED status for non-mmio devices"). The mt7925 Wi-Fi driver incorrectly dispatches a memory-mapped I/O (MMIO) specific event to non-MMIO buses, such as USB. This improper handling leads to a NULL pointer dereference when attempting to clean up DMA transmit queues. A remote attacker could exploit this vulnerability by sending specially crafted Wi-Fi packets, causing a system crash and resulting in a denial of service. MMIO-only TXRX_NOTIFY events are dispatched to mt7925_mac_tx_free(), calling unsupported queue ops.
Medium [CVE-2026-68191] fix NULL pointer dereference in rhash table destroy
In the Linux kernel, the following vulnerability has been resolved: wifi: ath12k: fix NULL pointer dereference in rhash table destroy When unbinding the ath12k driver, kernel NULL pointer dereferences occur in irq_work_sync() called from rhashtable_destroy(). Two hash tables are affected: 1. ath12k_link_sta hash table in ath12k_base 2. ath12k_dp_link_peer hash table in ath12k_dp The issue happens because the destroy functions are called unconditionally in cleanup paths, but the hash tables are only initialized late in their respective init functions. If the device was never fully started or if the init functions failed before initializing the hash tables, the pointers will be NULL. The issues are always reproducible from a VM because the MSI addressing initialization is failing. Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9; Red Hat package: kernel-rt.
Medium [CVE-2026-68190] fix OOB reads in rtw_get_wps_ie
In the Linux kernel, the following vulnerability has been resolved: staging: rtl8723bs: fix OOB reads in rtw_get_wps_ie() rtw_get_wps_ie() iterates over IE data from network frames without validating that the IE header and payload fit within the remaining buffer before reading them. Specifically: - in_ie[cnt + 1] is read without checking cnt + 1 < in_len - memcmp(&in_ie[cnt + 2],...) accesses cnt + 2 without bounds check - in_ie[cnt + 1] is used as length without verifying payload fits Add bounds checks at the top of the loop body to break early if fewer than 2 bytes remain for the IE header, or if the declared payload extends past the end of the buffer. Also require at least 4 bytes of payload before comparing the WPS OUI. The `rtw_get_wps_ie()` function, responsible for processing network frame data, fails to properly validate the size of incoming information elements (IEs). This oversight allows an attacker to trigger an out-of-bounds read, potentially leading to the disclosure of sensitive information or system instability. The vulnerability occurs when the driver attempts to read beyond the allocated buffer due to malformed IE data. This issue affects Realtek rtl8723bs Wi-Fi (staging). rtw_get_wps_ie() does not validate IE bounds before reading. Systems without rtl8723bs hardware are not affected.
Medium [CVE-2026-68187] fix unsigned loop counter wrap in transfer_args_to_stack
In the Linux kernel, the following vulnerability has been resolved: exec: fix unsigned loop counter wrap in transfer_args_to_stack() The stop value is derived from bprm->p >> PAGE_SHIFT. The index variable is an unsigned long. If bprm->p drops below PAGE_SIZE and stop becomes zero the loop condition index >= stop is always true. After the index == 0 iteration the decrement wraps to ULONG_MAX and bprm->page[ULONG_MAX] reads sizeof(void *) bytes in front of the array. The pointer has wrapped to -1. That garbage pointer is then passed to kmap_local_page() and PAGE_SIZE bytes are copied from wherever that lands into the stack of the process being created. And the loop doesn't terminate either... Getting there only requires bprm->p < PAGE_SIZE. On!MMU bprm_set_stack_limit() and bprm_hit_stack_limit() are empty. Count down from MAX_ARG_PAGES so the loop ends when index reaches stop, stop == 0 included. The iterations performed are unchanged for every other value of stop. Only CONFIG_MMU=n builds are affected, transfer_args_to_stack() is used by binfmt_flat and binfmt_elf_fdpic on nommu only. The loop predates git history. commit 7e7ec6a93434 ("elf_fdpic_transfer_args_to_stack(): make it generic") only moved it from binfmt_elf_fdpic.c into fs/exec.c and narrowed the copy to the used part of the first page. The condition and the decrement are unchanged from 2.6.12-rc2.
Medium [CVE-2026-68184] fix stack out-of-bounds read in CDROMVOLCTRL
In the Linux kernel, the following vulnerability has been resolved: cdrom: fix stack out-of-bounds read in CDROMVOLCTRL mmc_ioctl_cdrom_volume() first reads the audio control mode page into a 32-byte stack buffer with cgc->buflen set to 24. If the device reports a block descriptor, the function increases cgc->buflen to include that descriptor and reads the page again. For CDROMVOLCTRL, the function then builds a MODE SELECT parameter list by moving cgc->buffer forward by offset - 8 bytes. This drops the block descriptor from the outgoing payload and leaves a new 8-byte mode parameter header in front of the audio control page. However, cgc->buflen is left unchanged. With a standard 8-byte block descriptor, cgc->buffer points at buffer + 8 but cgc->buflen remains 32. cdrom_mode_select() therefore asks the low level packet path to write 32 bytes from that adjusted pointer, reading 8 bytes past the end of the 32-byte stack buffer. This is not hit by CDROMVOLREAD, and CDROMVOLCTRL only triggers it on drives that return a non-zero block descriptor length, which helps explain why it has gone unnoticed. The overread is also sent to the device as extra MODE SELECT payload, so it may not produce an obvious local failure. Reduce cgc->buflen by the same amount as the buffer pointer adjustment so the MODE SELECT transfer covers only the intended parameter list.
Medium [CVE-2026-68182] deal with premature interrupt
In the Linux kernel, the following vulnerability has been resolved: comedi: comedi_parport: deal with premature interrupt Syzbot reported a general protection fault in `comedi_get_is_subdevice_running()`, which was called from the interrupt handler `parport_interrupt()` in the "comedi_parport" driver, but it does not currently have a C reproducer for the problem. It's probably due to a premature interrupt for one of two reasons: 1. The driver sets up the interrupt handler before the comedi subdevices used by the interrupt handler have been allocated, but does not disable the interrupt in the parallel port's CTRL register first. 2. The driver uses a user-supplied I/O port base address which Syzbot would have supplied, but it might not be backed by real parallel port hardware. Change the initialization order in the driver's comedi "attach" handler (`parport_attach()`) so that the hardware registers are initialized before the interrupt handler is requested. This should prevent premature interrupts occurring for real hardware. Also add a test to the interrupt handler to ensure the comedi device is fully attached and return early if it isn't. A local user could trigger a premature interrupt, potentially due to incorrect initialization order of hardware registers or an invalid user-supplied I/O port address.
Medium [CVE-2026-68180] fix MSC output device reference leak
In the Linux kernel, the following vulnerability has been resolved: intel_th: fix MSC output device reference leak intel_th_output_open() looks up the output device with bus_find_device_by_devt(), which returns the device with a reference that must be dropped after use. commit 95fc36a234da ("intel_th: fix device leak on output open()") attempted to drop the reference from intel_th_output_release(). However, a successful open replaces file->f_op with the output driver file operations before returning, so close runs the output driver release callback instead. For MSC outputs, close runs intel_th_msc_release(), which only removes the per-file iterator and does not drop the device reference taken by intel_th_output_open(). Consequently, every successful MSC output open leaks one device reference. Drop the device reference from intel_th_msc_release(), which is the release path actually used for MSC output files. Remove the now-unused intel_th_output_release() callback from intel_th_output_fops. A flaw was found in the `intel_th` (Intel Trace Hub) driver within the Linux kernel. This vulnerability occurs because the `intel_th_output_open()` function acquires a device reference that is not properly released by the `intel_th_msc_release()` function when handling Message Signaled Interrupt (MSC) outputs.
Medium [CVE-2026-68178] pin the module while the device is open
In the Linux kernel, the following vulnerability has been resolved: misc: nsm: pin the module while the device is open misc_open() installs a misc driver's file operations with fops_get(), which pins file_operations::owner before replacing the file's f_op. The NSM misc device leaves nsm_dev_fops.owner unset, so opening /dev/nsm does not take a module reference on the nsm driver. If the driver is built as a module, an open file descriptor can therefore survive rmmod of the module that provides its ioctl callbacks. A later ioctl through that descriptor can call into unloaded module text. Set nsm_dev_fops.owner to THIS_MODULE so the misc core holds the module while any /dev/nsm file descriptor is open, matching the lifetime expectation for the installed file operations. A local user could exploit this by opening the `/dev/nsm` device and then unloading the NSM module. This allows a subsequent operation (ioctl) on the open file descriptor to call into memory that has been deallocated, potentially leading to arbitrary code execution or a denial of service. This issue affects NSM (Network Security Services) misc device. Module not pinned while /dev/nsm is open, allowing unload UAF. Systems without NSM hardware are not affected. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-763.
Medium [CVE-2026-68176] Fix mmiotrace possible NULL dereferencing of hiter->dev
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev If the mmio_pipe_open() fails to find a PCI device, the hiter->dev will be assigned to NULL. The mmiotrace read() function dereferences the hiter->dev if hiter exists. Change the test of the read to not only check hiter being NULL, but also the hiter->dev before dereferencing it. The `mmiotrace read()` function then attempts to dereference this null pointer, which can lead to a system crash and result in a denial of service. A local attacker could potentially exploit this to cause system instability. Systems not using mmiotrace are not affected. Red Hat severity: Low — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-476. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat OpenShift Container Platform 4. Will not fix / out of support: Red Hat Enterprise Linux 6. Red Hat does not currently list a fixing RHSA for this CVE. Affected products named by the advisory: Red Hat package: kernel-rt.
Medium [CVE-2026-68175] Fix resource leak on mmiotrace trace_pipe close
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix resource leak on mmiotrace trace_pipe close The mmiotrace tracer was added May 12th 2008. At that time, resources created in pipe_open() could not be freed because there was not pipe_close function pointer of the tracer. The pipe_close function pointer was added in December 7th, 2009, but the mmiotrace tracer was not updated. mmio_pipe_open() allocates a header_iter and takes a pci_dev reference when trace_pipe is opened. mmio_close() frees them, but it was only wired to the tracer's.close callback. tracing_release_pipe() invokes.pipe_close, not.close, when the trace_pipe file is released. As a result, closing trace_pipe with the mmiotrace tracer active leaked the header_iter allocation and left a stale pci_dev reference. Set.pipe_close to mmio_close, matching how function_graph wires both callbacks to the same handler. Note, if the trace_pipe is read to completion, it will clean up the resources, but if one were to run: # head -n 1 /sys/kernel/tracing/trace_pipe VERSION 20070824 Over and over again, it would trigger a massive leak. A local user could repeatedly read from the `trace_pipe` file without fully completing the read operation. This improper handling of resource cleanup leads to a significant memory leak and leaves stale references.
Medium [CVE-2026-68174] Fix union collision of module and refcnt for dynamic events
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix union collision of module and refcnt for dynamic events In 'struct trace_event_call', the 'module' pointer and the 'refcnt' atomic variable share the same memory space in a union. For dynamic events, the union member is 'refcnt', which acts as an active reference counter. When a dynamic event (such as kprobe, uprobe, fprobe, eprobe, or wprobe) has a non-zero reference count (e.g. due to active event triggers or perf attachments), its 'call->module' evaluates to a small non-zero integer instead of NULL. When filtering or setting events for a specific module (e.g., writing ':mod:' to 'set_event'), the code in '__ftrace_set_clr_event_nolock()' and 'update_event_fields()' reads 'call->module' directly without checking whether the event is dynamic. This causes the kernel to treat the small integer (refcnt) as a 'struct module' pointer, leading to a NULL/invalid pointer dereference (Oops) when dereferencing the module name. Fix this by ensuring that the 'TRACE_EVENT_FL_DYNAMIC' flag is checked before treating 'call->module' as a valid pointer in these code paths. When handling dynamic events, a memory collision occurs where a reference counter is mistakenly interpreted as a module pointer.
Medium [CVE-2026-68172] make huge_ptep_get handled unaligned addresses
In the Linux kernel, the following vulnerability has been resolved: arm64: make huge_ptep_get handled unaligned addresses huge_ptep_get() can be handed a virtual address pointing to the middle of a contpmd/contpte mapped hugetlb folio (examples of callers are pagemap_hugetlb_range, page_mapped_in_vma). The arm64 helper rewalks the pgtables in find_num_contig to answer whether the huge pte we have maps a contpmd or a contpte hugetlb folio, and returns CONT_PMDS or CONT_PTES, so that it can collect a/d bits over the contiguous ptes. We can falsely return CONT_PTES instead of CONT_PMDS if the addr is not aligned. On systems where CONT_PTES!= CONT_PMDS (meaning page size is 16K), we could collect excess A/D bit state, meaning extra work for the kernel. Even worse, we may iterate beyond the PTE table and dereference a garbage ptep pointer to access physical memory we don't own. Since the ptep pointer is a linear map address, we may run off the end of the linear map or into a hole, dereference a VA not mapped into the kernel pgtables and cause kernel panic. Fix this by aligning the pmdp pointer down to a contpmd base before checking equality with the passed huge pte pointer, to correctly answer whether the huge pte is the base of a contpmd block. A flaw was found in the Linux kernel, specifically within the `huge_ptep_get()` helper function for the arm64 architecture.
Medium [CVE-2026-68170] fix stale skb->sk reference on subflow close
In the Linux kernel, the following vulnerability has been resolved: mptcp: fix stale skb->sk reference on subflow close The backlog list is updated by mptcp_data_ready() under mptcp_data_lock(). The cleanup of backlog references to a closing subflow, however, was performed in mptcp_close_ssk(), before __mptcp_close_ssk() acquires the ssk lock, and while holding neither the ssk lock nor mptcp_data_lock(). Because that traversal ran without mptcp_data_lock(), concurrent softirq RX processing on another CPU (subflow_data_ready() -> mptcp_data_ready() -> __mptcp_add_backlog(), under mptcp_data_lock()) could add a backlog entry referencing the ssk while the cleanup loop was in progress. Such an entry could be missed by the cleanup, or the concurrent list update could corrupt the traversal, leaving skb->sk pointing at the ssk after it is freed. A later mptcp_backlog_purge() then dereferences the stale pointer, triggering a warning in inet_sock_destruct() (ssk->sk_rmem_alloc!= 0) followed by a use-after-free in mptcp_backlog_purge(). The cleanup runs only on the push path (MPTCP_CF_PUSH), where backlog references accumulate; on other teardown paths the caller already handles cleanup.
Medium [CVE-2026-68167] do not try compression for data reloc inodes
In the Linux kernel, the following vulnerability has been resolved: btrfs: do not try compression for data reloc inodes [BUG] There is a syzbot report that the check inside get_new_location() triggered: BTRFS info (device loop0): found 31 extents, stage: move data extents BTRFS info (device loop0): leaf 8908800 gen 16 total ptrs 28 free space 1676 owner 18446744073709551607 item 0 key (256 INODE_ITEM 0) itemoff 3835 itemsize 160 inode generation 5 transid 0 size 0 nbytes 0 block group 0 mode 40755 links 1 uid 0 gid 0 rdev 0 sequence 0 flags 0x0 atime 1669132761.0 ctime 1669132761.0 mtime 1669132761.0 otime 0.0 item 1 key (256 INODE_REF 256) itemoff 3823 itemsize 12 index 0 name_len 2 item 2 key (258 INODE_ITEM 0) itemoff 3663 itemsize 160 inode generation 1 transid 16 size 733184 nbytes 106496 block group 0 mode 100600 links 0 uid 0 gid 0 rdev 0 sequence 24 flags 0x18 item 3 key (258 EXTENT_DATA 0) itemoff 3595 itemsize 68 generation 16 type 0 inline extent data size 47 ram_bytes 4096 compression 1 [...] item 27 key (18446744073709551611 ORPHAN_ITEM 258) itemoff 2376 itemsize 0 BTRFS error (device loop0): unexpected non-zero offset in file extent item for data reloc inode 258 key offset 0 offset 9277520992061368337 ------------[ cut here ]------------ btrfs_abort_should_print_stack(__error) [CAUSE] The above dump tree shows the first file extent item is inlined, which should…
Medium [CVE-2026-68164] disallow overlapping input ranges for damon_set_regions
In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: disallow overlapping input ranges for damon_set_regions() damon_set_regions() assumes the input ranges are sorted by the address and don't overlap each other. Hence the assumption was initially to be explicitly validated. But commit 97d482f4592f ("mm/damon/sysfs: reuse damon_set_regions() for regions setting") has mistakenly removed the validation. This can make DAMON behave in unexpected ways. At the best, the monitoring results snapshot will just look weird since there will be overlapping regions. DAMOS will also work weirdly, applying the same action multiple times for overlapping regions, and make DAMOS quota weird. More seriously, depending on the setup and regions updates sequence, negative size regions can be made. It will trigger WARN_ONCE() if the kernel is built with CONFIG_DAMON_DEBUG_SANITY=y. Depending on the monitoring results, the negative size region can further trigger division by zero in damon_merge_two_regions(). Fix the problems by checking the assumption and returning an error if the input ranges don't meet the assumption. The issue was discovered [1] by Sashiko. A flaw was found in the Linux kernel's DAMON (Data Access MONitor) subsystem. Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9; Red Hat package: kernel-rt.
Medium [CVE-2026-68163] fix device-private PMD handling
In the Linux kernel, the following vulnerability has been resolved: mm/page_vma_mapped: fix device-private PMD handling Commit 65edfda6f3f2 ("mm/rmap: extend rmap and migration support device-private entries") introduced the concept of device-private PMD entries, but did not correctly update the rmap walk code to account for them. As a result, when page_vma_mapped_walk() encounters device-private PMD entries, it takes no action other than to acquire the PMD lock and exit. However this is highly problematic for two reasons - firstly, device private entries possess a PFN so check_pmd() needs to be called to ensure an overlapping PFN range. Secondly, and more importantly, if PVMW_MIGRATION is set the caller assumes the returned entry is a migration entry, resulting in memory corruption when the caller tries to interpret the device private entry as such. In addition, commit 146287290023 ("mm/huge_memory: implement device-private THP splitting") allowed device private PMDs to be split like THP mappings, but again did not update this code path. As a result, we might race a PMD split prior to acquiring the PMD lock. This patch addresses all of these issues by invoking check_pmd(), ensuring PMVW_MIGRATION is not set and checks whether a split raced us we do for PMD THP and migration entries.