CVE-2026-72113 can: bcm: add missing device refcount for CAN filter removal
A race condition in the Linux kernel CAN BCM module can lead to a use-after-free or memory leak when a device is unregistered concurrently, causing a denial of service.
- 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-2026-72113?
CVE-2026-72113 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: add missing device refcount for CAN filter removal
sashiko-bot remarked a problem with a concurrent device unregistration in isotp.c which also is present in the bcm.c code. A former fix for raw.c commit c275a176e4b6 ("can: raw: add missing refcount for memory leak fix") introduced a netdevice_tracker which solves the issue for bcm.c too.
bcm_release(), bcm_delete_rx_op() and bcm_notifier() relied on dev_get_by_index(ifindex) to re-find the device for an rx_op before unregistering its filter. If a concurrent NETDEV_UNREGISTER has already unlisted the device from the ifindex table, that lookup fails and can_rx_unregister() is silently skipped, leaving a stale CAN filter pointing at the soon-to-be-freed bcm_op/socket.
Hold a netdev_hold()/netdev_put() tracked reference on op->rx_reg_dev from the moment the rx filter is registered in bcm_rx_setup() until it is unregistered in bcm_rx_unreg(), and use that reference directly in bcm_release() and bcm_delete_rx_op() instead of re-looking the device up by ifindex.
Which versions are affected by CVE-2026-72113?
How do I fix CVE-2026-72113?
Apply the vendor's patch.
Is CVE-2026-72113 being exploited?
There is no known exploitation of CVE-2026-72113 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72113, DEBIAN-CVE-2026-72113, GHSA-q526-m4v6-prwf, UBUNTU-CVE-2026-72113.