In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_queue: hold nfnl mutex in event notifier We must serialize… (CVE-2026-98624)

The vulnerability in the Linux kernel netfilter nfnetlink_queue component was due to a lack of proper serialization between the release notifier and the config netlink function. This allowed a concurrent thread to invoke close(), triggering the release function while another socket process issued an UNBIND request for the same portid, leading to a general protection fault (kernel crash) in __instance_destroy. The fix involves holding the nfnl mutex in the event notifier to serialize these operations, preventing parallel UNBIND and URELEASE events. The patch is described as the shortest fix given that instances are not refcounted and the nfnetlink config callback drops the RCU read lock early due to sleeping allocations.

Exploitation of this vulnerability can cause a kernel crash (general protection fault), resulting in denial of service on affected systems. There is no indication of privilege escalation or code execution from the provided data.

A fix has been implemented that serializes the release notifier and config netlink function by holding the nfnl mutex in the event notifier. Users should apply the official Linux kernel update that includes this fix. Patch status is not explicitly confirmed in the provided data; therefore, check the vendor or Linux kernel advisory for the exact patch availability and remediation instructions.