Use-after-free in Linux kernel - CVE-2026-68178

Vulnerability details

The vulnerability allows a local user to execute code in kernel context.

The vulnerability exists due to use-after-free in the NSM misc device file operations handling in /dev/nsm when invoking ioctl on an open file descriptor after the nsm module has been unloaded. A local user can open /dev/nsm, keep the file descriptor open, and later issue an ioctl after module removal to execute code in kernel context.

The issue is exposed when the driver is built as a module and an open /dev/nsm file descriptor outlives removal of the module that provides the ioctl callbacks.

Affected software

How to mitigate CVE-2026-68178

External References

• https://git.kernel.org/stable/c/1996639f824ce9468395cdb7bcb8f467fa787e77
• https://git.kernel.org/stable/c/1da310b94504d42001e9c32c43c5dc105b777e5f
• https://git.kernel.org/stable/c/3b231f1e9990f4c21220d0a69733ce2105891ff9
• https://git.kernel.org/stable/c/9e9a82d00c3d10129fc310a7547b24a679d5d920

Related Security Bulletins

• Use-after-free in Linux kernel misc driver