A use-after-free vulnerability has been resolved in the Linux kernel's macvlan implementation. The vulnerability, identified as CVE-2026-23001, exists in the macvlan_forward_source() function and can be triggered due to missing RCU protection, potentially leading to code execution or denial of service.
In the Linux kernel, the following vulnerability has been resolved:
macvlan: fix possible UAF in macvlan_forward_source()
Add RCU protection on (struct macvlan_source_entry)->vlan.
Whenever macvlan_hash_del_source() is called, we must clear entry->vlan pointer before RCU grace period starts.
This allows macvlan_forward_source() to skip over entries queued for freeing.
Note that macvlan_dev are already RCU protected, as they are embedded in a standard netdev (netdev_priv(ndev)).
https: //lore.kernel.org/netdev/695fb1e8.050a0220.1c677c.039f.GAE@google.com/T/#u