CVE-2026-98624 netfilter: nfnetlink_queue: hold nfnl mutex in event notifier
A race condition in the Linux kernel netfilter module allows local attackers to cause a system crash via concurrent netlink operations.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98624?
CVE-2026-98624 is a vulnerability in Linux, published on 18 Oct 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: nfnetlink_queue: hold nfnl mutex in event notifier
We must serialize the release notifier and the config netlink function. A concurrent thread can issue close() which can call the release function while unrelated socket processes UNBIND request for same portid:
Oops: general protection fault, [..] RIP: 0010:__instance_destroy+0x60/0x210 [nfnetlink_queue] Call Trace: nfqnl_recv_config+0x9b0/0xdc0 [nfnetlink_queue] nfnetlink_rcv_msg+0x7c2/0xeb0 ? __pfx_nfnetlink_rcv_msg+0x10/0x10
After this, parallel UNBIND and URELEASE events are impossible.
This change isn't nice, but its the shortest fix given instances are not refcounted and the nfnetlink config callback drops the rcu read lock early due to need for sleeping allocations.
Which versions are affected by CVE-2026-98624?
How do I fix CVE-2026-98624?
Apply the vendor's patch.
Is CVE-2026-98624 being exploited?
There is no known exploitation of CVE-2026-98624 in the wild and no public exploit code.
Sources
Also known as AZL-109172, BELL-CVE-2026-98624, DEBIAN-CVE-2026-98624, GHSA-6phv-j3wg-rfjh, UBUNTU-CVE-2026-98624.