SB2026041423 - Use-after-free in Linux kernel netfilter
Published: April 14, 2026
Security Bulletin ID
SB2026041423
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Use-after-free (CVE-ID: CVE-2026-31414)
CWE-ID: CWE-416 - Use After Free
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a use-after-free in nf_conntrack_expect when dumping the helper name via ctnetlink or /proc. A local user can trigger access to freed conntrack helper state to cause a denial of service.
The issue involves unsafe use of nfct_help() without holding a reference to the master conntrack.
Remediation
Install update from vendor's website.
References
- https://git.kernel.org/stable/c/3dfd3f7712b5a800f2ba632179e9b738076a51f0
- https://git.kernel.org/stable/c/4bd1b3d839172724b33d8d02c5a4ff6a1c775417
- https://git.kernel.org/stable/c/847cb7fe26c5ce5dce0d1a41fac1ea488b7f1781
- https://git.kernel.org/stable/c/b53294bff19e56ada2f230ceb8b1ffde61cc3817
- https://git.kernel.org/stable/c/e7ccaa0a62a8ff2be5d521299ce79390c318d306
- https://git.kernel.org/stable/c/f01794106042ee27e54af6fdf5b319a2fe3df94d