CVE-2026-43116

A flaw was found in the netfilter: ctnetlink component of the Linux kernel. This vulnerability occurs due to insufficient locking when accessing the master conntrack object, allowing it to become invalid while still being referenced. A local attacker could potentially exploit this race condition, leading to a system crash and a denial of service.

ctnetlink expectation handling could keep a reference to the expectation object while the associated master conntrack object was freed concurrently. This leaves exp master as a stale pointer and can let get, delete, or event reporting paths access master conntrack state after it has gone away. For the CVSS the PR:L is used in the paranoid score because some deployments delegate CAP_NET_ADMIN or conntrack management inside network namespaces or containers to less privileged local users. The issue is not directly network reachable as a remote packet only attack, although traffic and conntrack activity can help create the concurrent state needed for the race. In the paranoid case, the stale master conntrack pointer is treated as a use after free candidate with possible confidentiality and integrity impact.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is to skip loading the affected module "netfilter" onto the system till we have a fix available, this can be done by a blacklist mechanism, this will ensure the driver is not loaded at the boot time.

How do I blacklist a kernel module to prevent it from loading automatically?
https://access.redhat.com/solutions/41278