CVE-2026-53000

/// Technical 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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References