CVE-2026-98251 openvswitch: avoid reallocating confirmed conntrack labels
A race condition in the Linux kernel's Open vSwitch module can cause a use-after-free when accessing conntrack labels, potentially leading to a system crash.
- 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-2026-98251?
CVE-2026-98251 is a high-severity 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:
openvswitch: avoid reallocating confirmed conntrack labels
ovs_ct_get_conn_labels() adds the labels extension when a conntrack entry does not have one. Confirmed conntracks can be read locklessly, so adding an extension may reallocate and free the extension block while another CPU accesses it.
Only add the extension for unconfirmed conntracks. A confirmed conntrack without labels now fails the caller's label operation instead of reallocating its extension storage.
Which versions are affected by CVE-2026-98251?
How do I fix CVE-2026-98251?
Apply the vendor's patch.
Is CVE-2026-98251 being exploited?
There is no known exploitation of CVE-2026-98251 in the wild and no public exploit code.
Sources
Also known as AZL-106350, BELL-CVE-2026-98251, DEBIAN-CVE-2026-98251, GHSA-6vh8-2x3v-qcxv, UBUNTU-CVE-2026-98251.