CVE-2026-53000 netfilter: nat: use kfree_rcu to release ops
A use-after-free vulnerability in the Linux kernel netfilter NAT module allows attackers to potentially execute code or escalate privileges via improper memory release.
- 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-2026-53000?
CVE-2026-53000 is a high-severity use after free vulnerability in Linux kernel, published on 24 Jun 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: nat: use kfree_rcu to release ops
Florian Westphal says:
"Historically this is not an issue, even for normal base hooks: the data path doesn't use the original nf_hook_ops that are used to register the callbacks.
However, in v5.14 I added the ability to dump the active netfilter hooks from userspace.
This code will peek back into the nf_hook_ops that are available at the tail of the pointer-array blob used by the datapath.
The nat hooks are special, because they are called indirectly from the central nat dispatcher hook. They are currently invisible to the nfnl hook dump subsystem though.
But once that changes the nat ops structures have to be deferred too."
Update nf_nat_register_fn() to deal with partial exposition of the hooks from error path which can be also an issue for nfnetlink_hook.
Weakness: CWE-763
Which versions are affected by CVE-2026-53000?
It affects 2 products.
Products include Linux kernel, Redhat Enterprise Linux.
How do I fix CVE-2026-53000?
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-2026-53000 being exploited?
There is no known exploitation of CVE-2026-53000 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-90372, BELL-CVE-2026-53000, DEBIAN-CVE-2026-53000, GHSA-6794-4vqv-w8qg, ROOT-OS-DEBIAN-12-CVE-2026-53000, ROOT-OS-DEBIAN-13-CVE-2026-53000 and 3 more.