ZDI-26-683: Linux Kernel IPv6 VTI Subsystem Use-After-Free Local Privilege Escalation Vulnerability
ZDI discloses CVE-2026-72463, a CVSS 7.5 use-after-free in the Linux Kernel IPv6 VTI subsystem enabling privilege escalation.
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.
ZDI discloses CVE-2026-72463, a CVSS 7.5 use-after-free in the Linux Kernel IPv6 VTI subsystem enabling privilege escalation.
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