CVE-2026-72115 can: bcm: track a single source interface for ANYDEV timeout/throttle ops
A race condition in the Linux kernel CAN BCM module allows concurrent frame processing to corrupt state and cause spurious timeouts, potentially 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-2026-72115?
CVE-2026-72115 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:
can: bcm: track a single source interface for ANYDEV timeout/throttle ops
An ANYDEV rx op (ifindex == 0) with an active RX timeout and/or throttle timer has no defined semantics when matching frames arrive from several interfaces: bcm_rx_handler() can run concurrently for the same op on different CPUs, racing hrtimer_cancel()/ bcm_rx_starttimer() against bcm_rx_timeout_handler() and causing spurious RX_TIMEOUT notifications and last_frames corruption. The same concurrency lets throttled multiplex frames from different interfaces clobber the single rx_ifindex/rx_stamp fields shared by the op.
Add op->if_detected to track the first interface that delivers a matching frame while a timeout/throttle timer is configured, and reject frames from any other interface for that op. The claim is decided in bcm_rx_handler() before hrtimer_cancel() touches op->timer, so a rejected frame can never disturb the claimed interface's watchdog. RTR-mode ops are excluded via RX_RTR_FRAME, independent of kt_ival1/kt_ival2, since those may briefly hold a stale value from an earlier non-RTR configuration.
The claim is released in bcm_notify() on NETDEV_UNREGISTER and in bcm_rx_setup() when SETTIMER reconfigures the timer values.
A (re-)claim is only possible on CAN devices in NETREG_REGISTERED dev->reg_state to cover the release in bcm_notify() where reg_state becomes NETREG_UNREGISTERING until synchronize_net().
Which versions are affected by CVE-2026-72115?
How do I fix CVE-2026-72115?
Apply the vendor's patch.
Is CVE-2026-72115 being exploited?
There is no known exploitation of CVE-2026-72115 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72115, DEBIAN-CVE-2026-72115, GHSA-hg3w-cj7m-96gr, UBUNTU-CVE-2026-72115.