High [CVE-2026-68178] Linux kernel: Arbitrary code execution or denial of service in NSM misc device via module unloading
This high-severity Red Hat Linux advisory covers CVE-2026-68178 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux for NVIDIA 26, Red Hat package: kernel.
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Summary
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.
Red Hat severity: Moderate — CVSS 7.8 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H). Weakness: CWE-763.
Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux for NVIDIA 26.
Affected products named by the advisory: Red Hat package: kernel.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
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