CVE-2026-31414 netfilter: nf_conntrack_expect: use expect->helper
A null pointer dereference in the Linux kernel netfilter subsystem allows local attackers to cause a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-31414?
CVE-2026-31414 is a critical vulnerability in Linux kernel, published on 13 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-476
Which versions are affected by CVE-2026-31414?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31414?
Apply the vendor's patch.
Is CVE-2026-31414 being exploited?
There is no known exploitation of CVE-2026-31414 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-82706, BELL-CVE-2026-31414, DEBIAN-CVE-2026-31414, GHSA-79r8-qx2r-f755, ROOT-OS-DEBIAN-11-CVE-2026-31414, ROOT-OS-DEBIAN-12-CVE-2026-31414 and 4 more.