CVE-2026-72463
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk6th percentile - higher than 6% of all known CVEs
Summary
In the Linux kernel's xfrm subsystem, a use-after-free vulnerability exists during async resumption. xfrm_rcv_cb may change skb->dev to a tunnel device without taking a reference, and subsequent resumption decrements the tunnel device's refcount, leading to use-after-free and refcount leak.
Risk Assessment
The vulnerability can lead to system crashes, network malfunction, or potential code execution by an attacker.
Recommendation
Apply a Linux kernel update containing the fix that stashes the original skb->dev and extends RCU protection over xfrm_rcv_cb and transport_finish.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: xfrm: Fix dev use-after-free in xfrm async resumption xfrm async resumption hold skb->dev refcnt until after transport_finish. However, xfrm_rcv_cb may modify skb->dev to tunnel dev without taking device reference, such as vti_rcv_cb. The subsequent async resumption will decrement the tunnel device's reference count, which lead to uaf of tunnel dev and refcnt leak of orig dev as below: unregister_netdevice: waiting for vti1 to become free. Usage count = -2 Stash the original skb->dev to fix refcnt imbalance. The new skb->dev set by xfrm_rcv_cb can race with device teardown. Extend rcu protection over xfrm_rcv_cb and transport_finish to prevent races.