CVE-2026-43116

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

netfilter: ctnetlink: ensure safe access to master conntrack

Holding reference on the expectation is not sufficient, the master

conntrack object can just go away, making exp->master invalid.

To access exp->master safely:

- Grab the nf_conntrack_expect_lock, this gets serialized with

clean_from_lists() which also holds this lock when the master

conntrack goes away.

- Hold reference on master conntrack via nf_conntrack_find_get().

Not so easy since the master tuple to look up for the master conntrack

is not available in the existing problematic paths.

This patch goes for extending the nf_conntrack_expect_lock section

to address this issue for simplicity, in the cases that are described

below this is just slightly extending the lock section.

The add expectation command already holds a reference to the master

conntrack from ctnetlink_create_expect().

However, the delete expectation command needs to grab the

/// 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