CVE-2026-72463: xfrm: Fix dev use-after-free in xfrm async resumption

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-15 · updated 2026-10-30

Description

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 products

Linux: from 6.12.94 before 6.12.112; from 6.18.23 before 6.18.54; from 6.1.191 before 6.2; from 6.6.160 before 6.7; from 6.19.13 before 6.20 — fixed in 6.12.112, 6.18.54, 6.2, 6.7, 6.20

How to fix

Upgrade to a fixed version: Linux 6.12.112, 6.18.54, 6.2, 6.7. Check the vendor advisory for mitigations.

References

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