CVE-2026-72297 net: atm: reject out-of-range traffic classes in QoS validation
An attacker can trigger an out-of-bounds read in the Linux kernel ATM subsystem by supplying invalid traffic classes, potentially leaking memory contents.
- 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-2026-72297?
CVE-2026-72297 is a high-severity vulnerability in Linux, published on 15 Aug 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:
net: atm: reject out-of-range traffic classes in QoS validation
Reject ATM traffic classes above ATM_ANYCLASS in check_tp(). SO_ATMQOS stores the supplied QoS after check_qos() succeeds, so accepting larger values leaves invalid traffic_class values in vcc->qos.
That bad state later reaches pvc_info(), which indexes class_name[] with vcc->qos.{rx,tp}.traffic_class. Values above ATM_ANYCLASS cause an out-of-bounds read when /proc/net/atm/pvc is read.
Tighten the existing QoS validation so invalid traffic_class values are rejected at the point where user supplied QoS is accepted.
Which versions are affected by CVE-2026-72297?
How do I fix CVE-2026-72297?
Apply the vendor's patch.
Is CVE-2026-72297 being exploited?
There is no known exploitation of CVE-2026-72297 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72297, DEBIAN-CVE-2026-72297, GHSA-2234-wg35-953c, UBUNTU-CVE-2026-72297.