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CVE-2025-21791 is a potential use-after-free vulnerability in the Linux kernel's VRF networking implementation. The l3mdev_l3_out() function can execute without Read-Copy-Update (RCU) read-side protection through the raw_sendmsg(), ip_push_pending_frames(), ip_send_skb(), ip_local_out(), __ip_local_out(), and l3mdev_ip_out() call path. Missing RCU protection permits a potential use-after-free during the affected operation. The fix adds an rcu_read_lock() and rcu_read_unlock() pair.
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A potential use-after-free vulnerability in the Linux kernel's VRF networking code caused by calling l3mdev_l3_out() without RCU protection. The fix adds an RCU read-lock/unlock pair. The advisory identifies affected Google Container-Optimized OS kernel packages and assigns a CVSS v3 base score of 7.8, with local access and low privileges required.
Linux kernel VRF L3 output RCU protection issue.
A Linux kernel VRF networking flaw in l3mdev_l3_out() that could result in a potential use-after-free due to missing RCU protection.
A Linux kernel VRF networking use-after-free vulnerability caused by l3mdev_l3_out() potentially executing without RCU protection.
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