Linux vulnerability

What happened

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.

Affected versions

Linux: 4236c30b437b80f673b9e08c8fae38b8d471ac9e through before fed4d3195a31125566876952ce66113ec1eb9008 (git); 0f451b43c88bf2b9c038b414be580efee42e031b through before 1acd93259b6be269e26be5d71c224bccd1f8352f (git); 1c428b03840094410c5fb6a5db30640486bbbfcb through before 63a30015199912bd5055bead8001b1ae68a67cdb (git); 1c428b03840094410c5fb6a5db30640486bbbfcb through before 8045c0df98d4f14c54e5cb875f1c9c0ce89fe4ff (git); 5002beda5cac69d522dc54da0d5d463ed9c963d2 (git); 6.12.94 through before 6.12.112 (semver); 6.18.23 through before 6.18.54 (semver); 6.19.13 through before 6.20 (semver); 7.0 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.