CVE-2026-31414

netfilter: nf_conntrack_expect: use expect->helper

State: Published
Severity: 9.8 Critical
Published: Apr 13, 2026
Updated: Oct 19, 2026
Reserved: Mar 9, 2026

Description

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_conntrack_expect: use expect->helper

Use expect->helper in ctnetlink and /proc to dump the helper name. Using nfct_help() without holding a reference to the master conntrack is unsafe.

Use exp->master->helper in ctnetlink path if userspace does not provide an explicit helper when creating an expectation to retain the existing behaviour. The ctnetlink expectation path holds the reference on the master conntrack and nf_conntrack_expect lock and the nfnetlink glue path refers to the master ct that is attached to the skb.

Scores

CVSS	Score	Vector	Source
3.1	9.8 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

CWE-476 NULL Pointer Dereference

Affected Products

Product	Versions
LinuxLinux	ea781f197d6a835cbb93a0bf88ee1696296ed8aa to before 847cb7fe26c5ce5dce0d1a41fac1ea488b7f1781Affected ea781f197d6a835cbb93a0bf88ee1696296ed8aa to before e7ccaa0a62a8ff2be5d521299ce79390c318d306Affected ea781f197d6a835cbb93a0bf88ee1696296ed8aa to before 4bd1b3d839172724b33d8d02c5a4ff6a1c775417Affected ea781f197d6a835cbb93a0bf88ee1696296ed8aa to before b53294bff19e56ada2f230ceb8b1ffde61cc3817Affected ea781f197d6a835cbb93a0bf88ee1696296ed8aa to before 3dfd3f7712b5a800f2ba632179e9b738076a51f0Affected ea781f197d6a835cbb93a0bf88ee1696296ed8aa to before f01794106042ee27e54af6fdf5b319a2fe3df94dAffected
LinuxLinux	2.6.30Affected before 2.6.30Not affected 6.1.168 through 6.1.Not affected 6.6.134 through 6.6.Not affected 6.12.81 through 6.12.Not affected 6.18.22 through 6.18.Not affected 6.19.12 through 6.19.*Not affected 7.0 and laterNot affected

Product

Versions

LinuxLinux

ea781f197d6a835cbb93a0bf88ee1696296ed8aa to before 847cb7fe26c5ce5dce0d1a41fac1ea488b7f1781Affected
ea781f197d6a835cbb93a0bf88ee1696296ed8aa to before e7ccaa0a62a8ff2be5d521299ce79390c318d306Affected
ea781f197d6a835cbb93a0bf88ee1696296ed8aa to before 4bd1b3d839172724b33d8d02c5a4ff6a1c775417Affected
ea781f197d6a835cbb93a0bf88ee1696296ed8aa to before b53294bff19e56ada2f230ceb8b1ffde61cc3817Affected
ea781f197d6a835cbb93a0bf88ee1696296ed8aa to before 3dfd3f7712b5a800f2ba632179e9b738076a51f0Affected
ea781f197d6a835cbb93a0bf88ee1696296ed8aa to before f01794106042ee27e54af6fdf5b319a2fe3df94dAffected

LinuxLinux

2.6.30Affected
before 2.6.30Not affected
6.1.168 through 6.1.*Not affected
6.6.134 through 6.6.*Not affected
6.12.81 through 6.12.*Not affected
6.18.22 through 6.18.*Not affected
6.19.12 through 6.19.*Not affected
7.0 and laterNot affected

References

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