Use-after-free in Linux kernel - CVE-2026-99117

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to use-after-free in the Linux kernel bridge multicast subsystem when tearing down port groups. A local user can trigger a teardown sequence in which deleting the iterator's saved next node prematurely terminates the port-group walk, leaving dangling port pointers that are subsequently accessed during a multicast database dump to cause a denial of service.

Affected software

How to mitigate CVE-2026-99117

External References

• https://git.kernel.org/stable/c/5a3f7a683aee56e1f15c9d53041f3236767eaae7
• https://git.kernel.org/stable/c/8243d587a081e790ad96e80d48eef44d9f7ef005
• https://git.kernel.org/stable/c/b45e8c24608c992d1e2cea047eb5bcbfa537f86b

Related Security Bulletins

• Use-after-free in Linux kernel bridge
• Debian update for linux