CVE-2026-45966 apparmor: fix NULL pointer dereference in __unix_needs_revalidation
A NULL pointer dereference in the Linux kernel's AppArmor module allows local attackers to cause a system crash via SCM_RIGHTS file descriptor passing.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-45966?
CVE-2026-45966 is a medium-severity vulnerability in Linux kernel, published on 27 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
apparmor: fix NULL pointer dereference in __unix_needs_revalidation
When receiving file descriptors via SCM_RIGHTS, both the socket pointer and the socket's sk pointer can be NULL during socket setup or teardown, causing NULL pointer dereferences in __unix_needs_revalidation().
This is a regression in AppArmor 5.0.0 (kernel 6.17+) where the new __unix_needs_revalidation() function was added without proper NULL checks.
The crash manifests as: BUG: kernel NULL pointer dereference, address: 0x0000000000000018 RIP: aa_file_perm+0xb7/0x3b0 (or +0xbe/0x3b0, +0xc0/0x3e0) Call Trace: apparmor_file_receive+0x42/0x80 security_file_receive+0x2e/0x50 receive_fd+0x1d/0xf0 scm_detach_fds+0xad/0x1c0
The function dereferences sock->sk->sk_family without checking if either sock or sock->sk is NULL first.
Add NULL checks for both sock and sock->sk before accessing sk_family.
Weakness: CWE-476
Which versions are affected by CVE-2026-45966?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-45966?
Apply the vendor's patch.
Is CVE-2026-45966 being exploited?
There is no known exploitation of CVE-2026-45966 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-45966, DEBIAN-CVE-2026-45966, GHSA-g4q8-m3pw-qhvv, UBUNTU-CVE-2026-45966.