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CVE-2026-31414

Critical · CVSS 9.8

Linux Kernel — Use-after-free / unsafe pointer dereference in netfilter conntrack expectation handling

CVSS
9.8
nvd
EPSS
0.38%
30th pct
KEV
No
Class
oss containerizable
NVD-CWE-noinfo

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.

Search profile — drives PoC discovery

Symbols nf_conntrack_expectexpect->helpernfct_helpexp->master->helperctnetlinknfnetlinknf_conntrack_expect lockmaster conntrack
Keywords CVE-2026-31414nf_conntrack_expectnetfilter conntrack expect helperctnetlink expectation helper namenfct_help unsafeLinux kernel netfilter PoCnf_conntrack_expect use-after-free
Versions: Linux kernel versions prior to fixes in commits 3dfd3f7712b5, 4bd1b3d83917, 847cb7fe26c5, b53294bff19e, e7ccaa0a62a8

Affected packages

Linux Kernel 2.6.30 → 6.1.168
Linux Kernel 6.13.0 → 6.18.22
Linux Kernel 6.19.0 → 6.19.12
Linux Kernel 6.2.0 → 6.6.134
Linux Kernel 6.7.0 → 6.12.81

References

Status: enriched · ingested 2026-07-14T18:00:20.000Z · profiled 2026-07-14T18:30:20.000Z