Red Hat Linux Linux Kernel Vulnerabilities & Security Advisories
2150 advisories tracked · Red Hat Security Data API · 1 listed in the CISA Known Exploited Vulnerabilities catalog
Every row below is a published Red Hat Linux advisory that VulniPulse classified as Linux Kernel, with the CVEs, affected and fixed releases and exploitation status the vendor stated. Severity mix: 782 high, 1365 medium, 1 low.
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Latest Red Hat Linux Kernel advisories
High [CVE-2026-64020] fix dma_vecs leak on p2p memory
In the Linux kernel, the following vulnerability has been resolved: nvme-pci: fix dma_vecs leak on p2p memory We don't unmap P2P memory, so we don't need to track it. The dma_vec allocation was getting leaked on the completion. This vulnerability occurs due to improper handling of peer-to-peer (P2P) memory, where dma_vec allocations are not correctly unmapped. This oversight leads to a memory leak, which can degrade system performance and potentially lead to a denial of service over an extended period. Red Hat severity: Moderate — CVSS 7.1 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H). Weakness: CWE-772. Affected Red Hat products: Red Hat Enterprise Linux 10. Red Hat does not currently list a fixing RHSA for this CVE. Affected products named by the advisory: Red Hat package: kernel.
High [CVE-2026-64027] rework the VALID marking (again)
In the Linux kernel, the following vulnerability has been resolved: net: shaper: rework the VALID marking (again) Recent commit changed the semantics from NOT_VALID to VALID. I didn't realize that the flags are not stored atomically with the entry in XArray. There's still a race of reader observing a VALID mark for a slot, getting interrupted, writer replacing the entry with a different one, reader continuing, fetching the entry which is now a different pointer than the pointer for which VALID was meant. The biggest consequence of this is that we may see a UAF since net_shaper_rollback() assumed that entries without VALID can be freed without observing RCU. Looks like the XArray marks are buying us nothing at this point. Let's convert the code to an explicit valid field. The smp_load_acquire() / smp_store_release() barriers are marginally cleaner. A race condition exists in how `VALID` marks are handled for entries in an XArray. This can lead to a Use-After-Free (UAF) vulnerability, where memory is incorrectly freed while still in use, potentially allowing an attacker to cause a denial of service or execute arbitrary code. Red Hat severity: Moderate — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-367. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9. Red Hat does not currently list a fixing RHSA for this CVE.
High [CVE-2026-63975] Fix possible crash on l2cap_ecred_conn_rsp
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix possible crash on l2cap_ecred_conn_rsp If dcid is received for an already-assigned destination CID the spec requires that both channels to be discarded, but calling l2cap_chan_del may invalidate the tmp cursor created by list_for_each_entry_safe and in fact it is the wrong procedure as the chan->dcid may be assigned previously it really needs to be disconnected. Calling l2cap_chan_clone directly may still lead to l2cap_chan_del so instead schedule l2cap_chan_timeout with delay 0 to close the channel asynchronously. A flaw was found in the Bluetooth L2CAP (Logical Link Control and Adaptation Protocol) component of the Linux kernel. When a device receives a connection response with an already-assigned destination Channel Identifier (CID), the system may crash. This occurs because the kernel's procedure for discarding both channels in this scenario can lead to incorrect channel deletion, causing instability. This vulnerability can be triggered by a remote attacker sending a specially crafted Bluetooth L2CAP packet, potentially leading to a denial of service. Red Hat severity: Moderate — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-825. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9.
High [CVE-2026-64029] Serialize UMP output teardown with event_input
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Serialize UMP output teardown with event_input seq_ump_process_event() borrows client->out_rfile.output without synchronizing with the first-open and last-close transition in seq_ump_client_open() and seq_ump_client_close(). The last output unuse can therefore drop opened[STR_OUT] to zero and release the rawmidi file while an in-flight event_input callback is still inside snd_rawmidi_kernel_write(). That leaves the rawmidi substream runtime exposed to teardown before the write path has taken its own buffer reference. Add a per-client rwlock for the event_input-visible output file. Publish a newly opened output file under the write side, and hold the read side from the output lookup through snd_rawmidi_kernel_write(). The last output close copies and clears the visible output file under the write side, then drops the lock and releases the saved rawmidi file. Use IRQ-safe rwlock guards because event_input can also be reached from atomic sequencer delivery. The buggy scenario involves two paths, with each column showing the order within that path: path A label: event_input path path B label: last unuse path 1. seq_ump_process_event() reads 1. seq_ump_client_close() client->out_rfile.output. drops opened[STR_OUT] to zero.
High [CVE-2026-63962] bound altmode_desc per iteration in svdm_consume_modes
In the Linux kernel, the following vulnerability has been resolved: usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes() svdm_consume_modes() checks pmdata->altmodes against the array size once before the loop over the count, but forgot to check the bound at every point in the loop. In the well-behaved SVDM discovery flow this is harmless because each of at most SVID_DISCOVERY_MAX SVIDs contributes at most MODE_DISCOVERY_MAX modes, exactly filling altmode_desc[ALTMODE_DISCOVERY_MAX]. But the CMDT_RSP_ACK handler in tcpm_pd_svdm() does not correlate an incoming ACK with any request the port actually sent. Once port->partner is set, an unsolicited Discover Modes ACK is consumed unconditionally. A broken or malicious port partner can therefore drive altmodes to ALTMODE_DISCOVERY_MAX - 1 via the normal flow, and then send one extra Discover Modes ACK with seven VDOs. Because the pre-loop check passes, the loop could then writes up to five entries past altmode_desc[]. For mode_data_prime the next field in struct tcpm_port is the partner_altmode[] pointer array, which then receives partner-chosen SVID/VDO bytes. Move the bound check inside the loop so the array can never be indexed past ALTMODE_DISCOVERY_MAX regardless of how many VDOs the partner supplies or how the function was reached.
High [CVE-2026-64007] refresh tcphdr after skb_ensure_writable
In the Linux kernel, the following vulnerability has been resolved: netfilter: synproxy: refresh tcphdr after skb_ensure_writable synproxy_tstamp_adjust() rewrites the TCP timestamp option in place and then patches the TCP checksum via inet_proto_csum_replace4() on the caller-supplied tcphdr pointer. Both ipv4_synproxy_hook() and ipv6_synproxy_hook() obtain that pointer with skb_header_pointer() before calling in, so it may either alias skb->head directly or point at the caller's on-stack _tcph buffer. Between obtaining the pointer and using it, the function calls skb_ensure_writable(skb, optend), which on a cloned or non-linear skb invokes pskb_expand_head() and frees the old skb->head. After that point the cached th is stale: caller (ipv[46]_synproxy_hook) th = skb_header_pointer(skb,..., &_tcph) synproxy_tstamp_adjust(skb, protoff, th,...) skb_ensure_writable(skb, optend) pskb_expand_head() /* kfree(old skb->head) */... inet_proto_csum_replace4(&th->check,...) /* writes into freed head, or into the caller's stack copy leaving the on-wire checksum stale */ The option bytes are written through skb->data and are fine; only the checksum update goes through th and so lands in the wrong place. The result is either a write into freed slab memory or a packet leaving with a checksum that does not match its payload.
High [CVE-2026-64002] free net->ipv4.sysctl_local_reserved_ports after unregister_net_sysctl_table
In the Linux kernel, the following vulnerability has been resolved: ipv4: free net->ipv4.sysctl_local_reserved_ports after unregister_net_sysctl_table() ipv4_sysctl_exit_net() is currently freeing net->ipv4.sysctl_local_reserved_ports too soon. Only after unregister_net_sysctl_table() we can be sure no threads can possibly use the sysctls, including /proc/sys/net/ipv4/ip_local_reserved_ports. A flaw was found in the Linux kernel's IPv4 networking component. The `ipv4_sysctl_exit_net()` function prematurely frees the `net->ipv4.sysctl_local_reserved_ports` memory. This can lead to a use-after-free vulnerability, where other threads might attempt to access deallocated memory. Such an issue can result in system instability or a denial of service. Red Hat severity: Important — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-825. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9. Red Hat does not currently list a fixing RHSA for this CVE. Affected products named by the advisory: Red Hat package: kernel-rt.
High [CVE-2026-63993] do not reuse cached ip_hdr value after skb_tunnel_check_pmtu
In the Linux kernel, the following vulnerability has been resolved: vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() skb_tunnel_check_pmtu() can change skb->head. Reusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF. Use instead ip_hdr(skb) as done in drivers/net/bareudp.c and drivers/net/geneve.c. Found by Sashiko. A flaw was found in the Linux kernel's Virtual Extensible LAN (VXLAN) module. This vulnerability occurs because a cached IP header pointer is improperly reused after a Path Maximum Transmission Unit (PMTU) check. When the packet's head is modified during the PMTU check, the old cached IP header pointer becomes invalid, leading to a Use-After-Free (UAF) condition. This memory corruption flaw can potentially allow an attacker to cause a system crash or execute arbitrary code. Red Hat severity: Important — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-825. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9. Red Hat does not currently list a fixing RHSA for this CVE. Affected products named by the advisory: Red Hat package: kernel-rt.
High [CVE-2026-64025] bpf, skmsg: fix verdict sk_data_ready racing with ktls rx
In the Linux kernel, the following vulnerability has been resolved: bpf, skmsg: fix verdict sk_data_ready racing with ktls rx sk_psock_strp_data_ready() already checks tls_sw_has_ctx_rx() and defers to psock->saved_data_ready when a TLS RX context is present, avoiding a conflict with the TLS strparser's ownership of the receive queue (commit e91de6afa81c, "bpf: Fix running sk_skb program types with ktls"). sk_psock_verdict_data_ready() has no equivalent guard. When a socket is inserted into a sockmap (BPF_SK_SKB_VERDICT) before TLS RX is configured, tls_sw_strparser_arm() saves sk_psock_verdict_data_ready as rx_ctx->saved_data_ready. On data arrival: tls_data_ready -> tls_strp_data_ready -> tls_rx_msg_ready -> saved_data_ready() = sk_psock_verdict_data_ready() -> tcp_read_skb() drains sk_receive_queue via __skb_unlink() without calling tcp_eat_skb(), so copied_seq is not advanced. tls_strp_msg_load() then finds tcp_inq() >= full_len (stale), calls tcp_recv_skb() on the now-empty queue, hits WARN_ON_ONCE(!first), and returns with rx_ctx->strp.anchor.frag_list pointing at a psock-owned (potentially freed) skb. tls_decrypt_sg() subsequently walks that frag_list: use-after-free. Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat package: kernel-rt.
High [CVE-2026-63979] hand off the pinned file reference to accept_doit
In the Linux kernel, the following vulnerability has been resolved: net/handshake: hand off the pinned file reference to accept_doit handshake_req_next() removes the request from the per-net pending list and drops hn_lock before handshake_nl_accept_doit() reads req->hr_sk->sk_socket and dereferences sock->file (once in FD_PREPARE() and again in get_file()). In that window a consumer running tls_handshake_cancel() followed by sockfd_put() (svc_sock_free) or __fput_sync() (xs_reset_transport) releases sock->file. sock_release() then runs sock_orphan(), zeroing sk_socket, and frees the struct socket. The accept-side code either reads NULL through sk_socket or chases freed memory. The submit-side sock_hold() does not prevent this. sk_refcnt protects struct sock, but struct socket and sock->file are independently refcounted via the file descriptor the consumer owns. Pinning sk leaves sock and sock->file unprotected. Retarget the accept-side dereferences at req->hr_file, which was pinned at submit time, instead of req->hr_sk->sk_socket->file. Pinning on its own is not sufficient: a consumer that cancels between handshake_req_next() returning and accept_doit reaching FD_PREPARE() takes the!remove_pending() branch in handshake_req_cancel() and drops hr_file before the accept side takes its own reference.
High [CVE-2026-64015] fix missed RCU read section on lookup
In the Linux kernel, the following vulnerability has been resolved: security/keys: fix missed RCU read section on lookup Nicholas Carlini reports that the keyring code calls assoc_array_find() in find_key_to_update() without holding the RCU read lock, while the assoc_array_gc() code really is designed around removing the node from the tree and then freeing it after an RCU grace-period. The regular key handling doesn't see this because holding the keyring semaphore hides any lifetime issues, but the persistent key handling uses a different model. Instead of extending the keyring locking, just do the simple RCU locking that the assoc_array was designed for. The `assoc_array_find()` function, used for looking up keys, was called without holding the necessary Read-Copy-Update (RCU) read lock. This oversight allows for a memory corruption vulnerability, particularly affecting persistent key handling, as the system's garbage collection mechanism can free memory while it is still in use. This could lead to a denial of service. Red Hat severity: Moderate — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-825. 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. Will not fix / out of support: Red Hat Enterprise Linux 6.
High [CVE-2026-63978] Drain pending requests at net namespace exit
In the Linux kernel, the following vulnerability has been resolved: net/handshake: Drain pending requests at net namespace exit The arguments to list_splice_init() in handshake_net_exit() are reversed. The call moves the local empty "requests" list onto hn->hn_requests, leaving the local list empty, so the subsequent drain loop runs zero iterations. Pending handshake requests that had not yet been accepted are not torn down when the net namespace is destroyed; each one keeps a reference on a socket file and on the handshake_req allocation. Pass the source and destination in the documented order (list_splice_init(list, head) moves list onto head) so the pending list is transferred to the local scratch list and drained through handshake_complete(). Fixing the splice direction exposes a list-corruption race. After the splice each req->hr_list still has non-empty link pointers, threading the stack-local scratch list rather than hn_requests. A concurrent handshake_req_cancel() -- for example, from sunrpc's TLS timeout on a kernel socket whose netns reference was not taken -- finds the request through the rhashtable, calls remove_pending(), and sees!list_empty(&req->hr_list). __remove_pending_locked() then list_del_init()s an entry off the scratch list while the drain iterates, corrupting it.
High [CVE-2026-64034] Fix TOCTOU double-fetch of hwc_msg_id from DMA buffer
In the Linux kernel, the following vulnerability has been resolved: net: mana: Fix TOCTOU double-fetch of hwc_msg_id from DMA buffer In mana_hwc_rx_event_handler(), resp->response.hwc_msg_id is read from DMA-coherent memory and bounds-checked, then mana_hwc_handle_resp() re-reads the same field from the same DMA buffer for test_bit() and pointer arithmetic. DMA-coherent memory is mapped uncacheable on x86 and is shared, unencrypted, in Confidential VMs (SEV-SNP/TDX), so each load goes directly to host-visible memory. A H/W can modify the value between the check and the use, bypassing the bounds validation. Fix this by reading hwc_msg_id exactly once using READ_ONCE() into a stack-local variable in mana_hwc_rx_event_handler(), and passing the validated value as a parameter to mana_hwc_handle_resp(). A flaw was found in the Linux kernel's mana network driver. This Time-of-Check to Time-of-Use (TOCTOU) vulnerability allows a hardware component to modify a message identifier (hwc_msg_id) in Direct Memory Access (DMA) memory after it has been validated but before it is used. This manipulation bypasses critical bounds validation, potentially leading to unexpected system behavior or security bypasses, particularly in Confidential Virtual Machines (CVMs) where DMA memory is shared and unencrypted. Red Hat severity: Moderate — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H).
High [CVE-2026-63984] fix hdrlen overflow in ipv6_rpl_srh_decompress
In the Linux kernel, the following vulnerability has been resolved: ipv6: rpl: fix hdrlen overflow in ipv6_rpl_srh_decompress() ipv6_rpl_srh_decompress() computes: outhdr->hdrlen = (((n + 1) * sizeof(struct in6_addr)) >> 3); hdrlen is __u8. For n >= 127 the result exceeds 255 and silently truncates. With n=127 (cmpri=15, cmpre=15, pad=0, hdrlen=16): (128 * 16) >> 3 = 256, truncated to 0 as __u8 The caller in ipv6_rpl_srh_rcv() then places the compressed header at buf + ((ohdr->hdrlen + 1) 255, which prevents n+1 from overflowing unsigned char (the segments_left field), but does not prevent the computed hdrlen from overflowing __u8. n=127 passes because 128 127. This caps n at 126, giving hdrlen = (127 * 16) >> 3 = 254, which fits in __u8. The compressed header then lands at buf + ((254 + 1) << 3) = buf + 2040, exactly past the decompressed region (buf[0..2039]). 127 segments is well beyond any realistic RPL deployment. A flaw was found in the Linux kernel's IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) segment routing header (SRH) decompression function, ipv6_rpl_srh_decompress(). An integer overflow occurs when processing a specially crafted IPv6 packet, causing the header length calculation to truncate. This vulnerability could allow a remote attacker to cause data corruption.
High [CVE-2026-64001] Fix setup list UAF on proc write error
In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: oss: Fix setup list UAF on proc write error snd_pcm_oss_proc_write() links a newly allocated setup entry into the OSS setup list before duplicating the task name. If the task-name allocation fails, the error path frees the already linked entry and leaves setup_list pointing at freed memory. A later OSS device open can then walk the stale list entry in snd_pcm_oss_look_for_setup() and dereference freed memory. Allocate the task name and initialize the setup entry before publishing the entry on setup_list. Also fetch the initial proc read iterator only after taking setup_mutex, so all setup_list traversal follows the same list lifetime rules. A flaw was found in the Linux kernel's ALSA (Advanced Linux Sound Architecture) PCM (Pulse Code Modulation) OSS (Open Sound System) component. A local user could exploit a Use-After-Free (UAF) vulnerability in the `snd_pcm_oss_proc_write()` function. This occurs when a setup entry is prematurely linked into the OSS setup list, and a subsequent task-name allocation failure leads to the entry being freed while still referenced. A later attempt to open an OSS device could then access this freed memory, potentially leading to memory corruption or system instability. Red Hat severity: Moderate — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H).
High [CVE-2026-64009] Check for underflow in xfrm_state_mtu
In the Linux kernel, the following vulnerability has been resolved: xfrm: Check for underflow in xfrm_state_mtu Leo Lin reported OOB write issue in esp component: xfrm_state_mtu() returns u32 but performs its arithmetic in unsigned modulo-2^32 space using an attacker-influenced "header_len + authsize + net_adj" subtracted from a small "mtu" argument. A nobody user can install an IPv4 ESP tunnel SA with a large authentication key (XFRMA_ALG_AUTH_TRUNC, e.g. hmac(sha512), 64-byte key, 64-byte trunc), configure a small interface MTU (68 bytes), and set XFRMA_TFCPAD to a large value. When a single UDP datagram is then sent through the tunnel, xfrm_state_mtu() underflows to a near-2^32 value, and esp_output() consumes it as a signed int via: padto = min(x->tfcpad, xfrm_state_mtu(x, mtu_cached)) esp.tfclen = padto - skb->len (assigned to int) esp.tfclen ends up negative (e.g. -207). It is sign-extended to size_t when passed to memset() inside esp_output_fill_trailer(), producing a ~16 EB write of zeroes at skb_tail_pointer(skb). KASAN logs it as "Write of size 18446744073709551537 at addr ffff888...". This causes the sendmsg attempt to fail with ENETUNREACH. A local, unprivileged user can trigger an integer underflow in the Encapsulating Security Payload (ESP) module's Maximum Transmission Unit (MTU) calculation.
High [CVE-2026-63987] cap profile updates at NET_DIM_PARAMS_NUM_PROFILES
In the Linux kernel, the following vulnerability has been resolved: ethtool: coalesce: cap profile updates at NET_DIM_PARAMS_NUM_PROFILES ethnl_update_profile() walks the ETHTOOL_A_PROFILE_IRQ_MODERATION nest list with an index 'i' and writes new_profile[i++] without bounding i. The destination is kmemdup()'d at NET_DIM_PARAMS_NUM_PROFILES entries (5), but the Netlink nest count is entirely user-controlled. Netlink policies do not have support for constraining the number of nested entries (or number of multi-attr entries). The ethnl_update_profile() function, responsible for updating profile settings, does not properly validate user-controlled input when processing Netlink nest lists. This allows a local attacker to cause an out-of-bounds write, potentially leading to a denial of service or other memory corruption issues. Red Hat severity: Moderate — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-787. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9. Red Hat does not currently list a fixing RHSA for this CVE. Affected products named by the advisory: Red Hat package: kernel-rt.
High [CVE-2026-63970] bind uarg before filling zerocopy skb
In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: bind uarg before filling zerocopy skb virtio_transport_send_pkt_info() allocates or reuses the zerocopy uarg before entering the send loop, but virtio_transport_alloc_skb() still fills the skb before it inherits that uarg. When fixed-buffer vectored zerocopy hits MAX_SKB_FRAGS, io_sg_from_iter() may partially attach managed frags and return -EMSGSIZE. The rollback path call kfree_skb() to free an skb that carries SKBFL_MANAGED_FRAG_REFS but no uarg, so skb_release_data() falls through to ordinary frag unref. Pass the uarg into virtio_transport_alloc_skb() and bind it immediately before virtio_transport_fill_skb(). This keeps control or no-payload skbs untouched while ensuring success and rollback share one lifetime rule. This vulnerability occurs when the system processes zerocopy socket buffers (skbs) and encounters an error during memory allocation for fixed-buffer vectored data. The system may attempt to free memory incorrectly, leading to a use-after-free condition or memory corruption. This can potentially allow a local attacker to cause a denial of service or escalate their privileges on the system. Red Hat severity: Important — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-825. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9.
High [CVE-2026-63981] Fix blockcast recursion bypass leading to stack overflow
In the Linux kernel, the following vulnerability has been resolved: net/sched: act_mirred: Fix blockcast recursion bypass leading to stack overflow tcf_mirred_act() checks sched_mirred_nest against MIRRED_NEST_LIMIT (4) to prevent deep recursion. However, when the action uses blockcast (tcfm_blockid!= 0), the function returns at the tcf_blockcast() call BEFORE reaching the counter increment. As a result, the recursion counter never advances and the limit check is entirely bypassed. When two devices share a TC egress block with a mirred blockcast rule, a packet egressing on device A is mirrored to device B via blockcast; device B's egress TC re-enters tcf_mirred_act() via blockcast and mirrors back to A, creating an unbounded recursion loop: tcf_mirred_act -> tcf_blockcast -> tcf_mirred_to_dev -> dev_queue_xmit -> sch_handle_egress -> tcf_classify -> tcf_mirred_act -> (repeat) This recursion continues until the kernel stack overflows. The bug is reachable from an unprivileged user via unshare(CLONE_NEWUSER | CLONE_NEWNET): user namespaces grant CAP_NET_ADMIN in the new network namespace, which is sufficient to create dummy devices, attach clsact qdiscs with shared blocks, and install mirred blockcast filters. Affected products named by the advisory: Red Hat Enterprise Linux 6; Red Hat package: kernel.
High [CVE-2026-63996] require exact CDB reply length
In the Linux kernel, the following vulnerability has been resolved: ethtool: cmis: require exact CDB reply length Malicious SFP module could respond with rpl_len longer than what cmis_cdb_process_reply() expected, leading to OOB writes. Malicious HW is a bit theoretical but some modules may just be buggy and/or the reads may occasionally get corrupted, so let's protect the kernel. The existing check protects from short replies. We need to protect from long ones, too. All callers that pass a non-zero rpl_exp_len cast the reply payload to a fixed-layout struct and read fields at fixed offsets, with no version negotiation or short-reply handling: - cmis_cdb_validate_password() - cmis_cdb_module_features_get() - cmis_fw_update_fw_mng_features_get() so let's assume that responses longer than expected do not have to be handled gracefully here. Add a warning message to make the debug easier in case my understanding is wrong... Note that page_data->length (argument of kmalloc) comes from last arg to ethtool_cmis_page_init() which is rpl_exp_len. Note2 that AIs also like to point out overflows in args->req.payload itself (which is a fixed-size 120 B buffer, on the stack), but callers should be reading structs defined by the standard, so protecting from requests for more data than max seem like defensive programming.