AppArmor NULL ptr deref in __unix_needs_revalidation (Linux kernel)
CVE-2026-45966 Published on May 27, 2026
apparmor: fix NULL pointer dereference in __unix_needs_revalidation
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.
Products Associated with CVE-2026-45966
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Affected Versions
Linux:- Version 88fec3526e84123997ecebd6bb6778eb4ce779b7 and below fea017a7f6abe179decf575a2d8464c74edb3964 is affected.
- Version 88fec3526e84123997ecebd6bb6778eb4ce779b7 and below e85bc9101afc4202aa2269967ce9d3ffbecd0994 is affected.
- Version 88fec3526e84123997ecebd6bb6778eb4ce779b7 and below e2938ad00b21340c0362562dfedd7cfec0554d67 is affected.
- Version 6.17 is affected.
- Before 6.17 is unaffected.
- Version 6.18.14, <= 6.18.* is unaffected.
- Version 6.19.4, <= 6.19.* is unaffected.
- Version 7.0, <= * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.