Race condition in Linux kernel - CVE-2026-99175

Vulnerability details

The vulnerability allows a local user to cause a denial of service by triggering a kernel NULL pointer dereference.

The vulnerability exists due to a race condition in the Linux kernel fsnotify connector teardown when new notification marks are inserted while fsnotify_destroy_marks() destroys existing marks. A local user can race an inotify watch re-addition and an fdinfo read against connector teardown to trigger a call to igrab(NULL), causing a kernel crash.

Affected software

How to mitigate CVE-2026-99175

External References

• https://git.kernel.org/stable/c/36ebddca56b9d8993d6dc984fdecc748ee1f5e06
• https://git.kernel.org/stable/c/472589eacdf10b5f9bd10b333957ed5291b2544b
• https://git.kernel.org/stable/c/952501bfc6e5e654ac4a17ec9d90c1ec614bd9f1

Related Security Bulletins

• Race condition in Linux kernel fsnotify connector teardown in fs/notify/mark.c, particularly fsnotify_destroy_marks()
• Debian update for linux