CVE-2026-52912
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk4th percentile - higher than 4% of all known CVEs
Summary
A use-after-free vulnerability was found in the Linux kernel's netfilter queue (NFQUEUE) for bridged packets. br_pass_frame_up() changes skb->dev to the bridge master before queuing, but NFQUEUE does not hold a reference to this device, leading to a use-after-free when the packet is reinjected after the bridge is removed.
Risk Assessment
An attacker could exploit this vulnerability to escalate privileges or cause a denial of service (DoS) by sending crafted bridged packets that, after queuing and bridge removal, access freed memory.
Recommendation
Immediately update the Linux kernel to a version containing the fix that stores and holds a reference to skb->dev in the queue entry and uses the saved device during NETDEV_DOWN handling.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_queue: hold bridge skb->dev while queued br_pass_frame_up() rewrites skb->dev from the ingress port to the bridge master before queueing bridge LOCAL_IN packets. NFQUEUE only holds references on state.in/out and bridge physdevs, so a queued bridge packet can retain a freed bridge master in skb->dev until reinjection. When the verdict is reinjected later, br_netif_receive_skb() re-enters the receive path with skb->dev still pointing at the freed bridge master, triggering a use-after-free. Store skb->dev in the queue entry, hold a reference on it for the queue lifetime, and use the saved device when dropping queued packets during NETDEV_DOWN handling.