CVE-2026-80636: netfilter: conntrack: revert ct extension genid infrastructure
In the Linux kernel, the following vulnerability has been resolved:
netfilter: conntrack: revert ct extension genid infrastructure
This infrastructure is not used anymore after moving ct timeout and helper to use datapath refcount to track object use.
Revert commit c56716c69ce1 ("netfilter: extensions: introduce extension genid count") this patch disables all ct extensions (leading to NULL) for unconfirmed conntracks, when this is only targeted at ct helper and ct timeout. There is also codebase that dereferences the ct extension without checking for NULL which could lead to crash.
Affected Software
Event History
Frequently Asked Questions
Which conntrack state is implicated by the faulty behavior?
The issue involves unconfirmed conntrack entries. The affected change disabled all conntrack extensions for those entries, even though the intended scope was limited to conntrack helper and timeout handling.
What is the practical impact if affected code dereferences an extension?
Code paths that dereference a conntrack extension without checking for NULL can crash the kernel. This creates an availability risk.