CVE-2026-72113
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk6th percentile - higher than 6% of all known CVEs
Summary
In the Linux kernel, the CAN BCM module lacks proper device refcounting during CAN filter removal. Functions bcm_release(), bcm_delete_rx_op(), and bcm_notifier() relied on re-looking up the device by ifindex, which could fail during concurrent unregistration, leaving a stale filter. The patch adds holding a reference on op->rx_reg_dev from filter registration to unregistration.
Risk Assessment
This can lead to use-after-free or improper filter removal, potentially destabilizing the system.
Recommendation
Apply the kernel patch that adds proper device reference holding in the CAN BCM module.
Original NVD description (English source)
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.