CVE-2026-53220 netfilter: revalidate bridge ports
A missing NULL check in the Linux kernel netfilter bridge code allows a local attacker to cause a kernel panic via a race condition.
- 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-2026-53220?
CVE-2026-53220 is a medium-severity vulnerability in Linux kernel, published on 25 Jun 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: revalidate bridge ports
ebt_redirect_tg() dereferences br_port_get_rcu() return without a NULL check, causing a kernel panic when the bridge port has been removed between the original hook invocation and an NFQUEUE reinject.
A mere NULL check isn't sufficient, however. As sashiko review points out userspace can not only remove the port from the bridge, it could also place the device in a different virtual device, e.g. macvlan.
If this happens, we must drop the packet, there is no way for us to reinject it into the bridge path.
Switch to _upper API, we don't need the bridge port structure. Also, this fix keeps another bug intact:
Both nfnetlink_log and nfnetlink_queue use CONFIG_BRIDGE_NETFILTER too aggressive, which prevents certain logging features when queueing in bridge family: NETFILTER_FAMILY_BRIDGE can be enabled while the old CONFIG_BRIDGE_NETFILTER cruft is off.
Fixes tag is a common ancestor, this was always broken.
Weakness: CWE-476
Which versions are affected by CVE-2026-53220?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-53220?
Apply the vendor's patch.
Is CVE-2026-53220 being exploited?
There is no known exploitation of CVE-2026-53220 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-90729, BELL-CVE-2026-53220, DEBIAN-CVE-2026-53220, GHSA-7q5m-qv9w-c8xx, ROOT-OS-DEBIAN-11-CVE-2026-53220, ROOT-OS-DEBIAN-12-CVE-2026-53220 and 3 more.