CVE-2026-23392 netfilter: nf_tables: release flowtable after rcu grace period on error
A use-after-free vulnerability in the Linux kernel netfilter subsystem allows attackers to potentially execute code or cause a denial of service via specific error paths.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23392?
CVE-2026-23392 is a high-severity use after free vulnerability in Linux kernel, published on 25 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: release flowtable after rcu grace period on error
Call synchronize_rcu() after unregistering the hooks from error path, since a hook that already refers to this flowtable can be already registered, exposing this flowtable to packet path and nfnetlink_hook control plane.
This error path is rare, it should only happen by reaching the maximum number hooks or by failing to set up to hardware offload, just call synchronize_rcu().
There is a check for already used device hooks by different flowtable that could result in EEXIST at this late stage. The hook parser can be updated to perform this check earlier to this error path really becomes rarely exercised.
Uncovered by KASAN reported as use-after-free from nfnetlink_hook path when dumping hooks.
Weakness: CWE-416
Which versions are affected by CVE-2026-23392?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-23392?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-23392 being exploited?
There is no known exploitation of CVE-2026-23392 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-80585, BELL-CVE-2026-23392, DEBIAN-CVE-2026-23392, GHSA-f5vj-m443-mgw6, ROOT-OS-DEBIAN-11-CVE-2026-23392, ROOT-OS-DEBIAN-12-CVE-2026-23392 and 4 more.