Use-after-free in Linux kernel - CVE-2026-99167

Vulnerability details

The vulnerability allows a local user to potentially cause a denial of service through kernel memory corruption.

The vulnerability exists due to a use-after-free in __tcf_action_put() in the Linux kernel traffic control subsystem when concurrent operations release an action. A local user can trigger concurrent action releases to potentially cause a kernel crash: another thread may free the action after its reference count is decremented but before its binding count is updated, causing a write to freed memory.

Affected software

How to mitigate CVE-2026-99167

External References

• https://git.kernel.org/stable/c/2465d27ef90de9105c2bffb6c35f8ce08918e642
• https://git.kernel.org/stable/c/2e012e431aa271ef3c84206f48854f539c03bff0
• https://git.kernel.org/stable/c/7b16eb911091aae237a8673da94e4dfb9cd21d54

Related Security Bulletins

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