CVE-2026-97436 dpaa2-switch: rework FDB management on the bridge leave path
A logic error in the Linux kernel dpaa2-switch driver causes FDB exhaustion when ports leave bridges, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-97436?
CVE-2026-97436 is a denial of service vulnerability in Linux, published on 24 Sep 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:
dpaa2-switch: rework FDB management on the bridge leave path
On bridge leave, the dpaa2_switch_port_set_fdb() function always allocates a new FDB for the port which is becoming standalone. In case no FDB is found, then the port leaving a bridge will continue to use the current one.
The above logic does not cover the case in which there are multiple bridges which have ports from the same DPSW instance. In this case, when the last port leaves bridge #1, it finds an unused FDB to switch to, but the old FDB is not marked as unused. Since the number of FDBs is equal to the number of DPSW interfaces, this will eventually lead to multiple ports sharing the same FDB.
Fix this by changing how we are managing the FDBs on the leave path. Instead of directly allocating a new FDB, first verify if the current port is the last one to leave a bridge. If this is the case, then continue to use the current FDB and only allocate another FDB if there are other ports remaining in the bridge.
Which versions are affected by CVE-2026-97436?
How do I fix CVE-2026-97436?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-97436 being exploited?
There is no known exploitation of CVE-2026-97436 in the wild and no public exploit code.
Sources
Also known as AZL-103619, BELL-CVE-2026-97436, DEBIAN-CVE-2026-97436, GHSA-6rj6-xm99-p85m, UBUNTU-CVE-2026-97436.