CVE-2026-74661 addresses a use-after-free vulnerability in the Linux kernel's mac802154 subsystem. Specifically, mac802154_beacon_worker() reads local->beacon_req under RCU protection and derives the sub-interface from the request. However, after dropping the RCU read lock, it continues to use the sub-interface and embedded wpan_dev, which may have been freed by mac802154_stop_beacons_locked() during interface teardown. The flaw arises because the beacon worker does not hold a netdev reference to ensure the lifetime of these objects. The patch applies the same lifetime management as the scan worker by taking a netdev reference while the request is protected by RCU and releasing it on all code paths after the reference is acquired, preventing use-after-free conditions.

The vulnerability could lead to use-after-free memory corruption within the Linux kernel's mac802154 network subsystem. This may cause kernel crashes or undefined behavior, potentially impacting system stability or security. No information about active exploitation or broader impact is provided.

A fix has been implemented in the Linux kernel to address this vulnerability by properly managing netdev references in the beacon worker. Users should apply the official kernel updates that include this patch once available. Patch status is not explicitly confirmed in the provided data; therefore, check the vendor or Linux kernel advisory for current remediation guidance.