CVE-2026-98320 netfilter: flowtable: hold reference on ct until flow is released
A use-after-free in the Linux kernel netfilter flowtable allows attackers to execute arbitrary code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98320?
CVE-2026-98320 is a high-severity use after free vulnerability in Linux, published on 6 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: flowtable: hold reference on ct until flow is released
nf_ct_put() releases the ct->ext area inmediately, the rcu typesafe semantics also allow to refer to the wrong conntrack from the flowtable datapath. Hold reference on ct until flow is released after rcu grace period.
Add rcu_barrier() on module exit path, to ensure pending flow entries are release before module goes away.
Which versions are affected by CVE-2026-98320?
How do I fix CVE-2026-98320?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-98320 being exploited?
There is no known exploitation of CVE-2026-98320 in the wild and no public exploit code.
Sources
Also known as AZL-106083, BELL-CVE-2026-98320, DEBIAN-CVE-2026-98320, GHSA-7rm7-mf5x-673x, UBUNTU-CVE-2026-98320.