CVE-2026-31663: Linux Kernel

High severity, CVSS 7.8. EPSS: 0.1% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: xfrm: hold dev ref until after transport_finish NF_HOOK After async crypto completes, xfrm_input_resume() calls dev_put() immediately on re-entry before the skb reaches transport_finish. The skb->dev pointer is then used inside NF_HOOK and its okfn, which can race with device teardown. Remove the dev_put from the async resumption entry and instead drop the reference after the NF_HOOK call in transport_finish, using a saved device pointer since NF_HOOK may consume the skb. This covers NF_DROP, NF_QUEUE and NF_STOLEN paths that skip the okfn. For non-transport exits (decaps, gro, drop) and secondary async return points, release the reference inline when async is set.

Affected products

• Linux Linux Kernel: from 3.2.100, before 3.3 (fixed in 3.3); from 3.16.55, before 3.17 (fixed in 3.17); from 4.14.24, before 4.15 (fixed in 4.15); from 4.15.1, before 6.18.23 (fixed in 6.18.23); from 6.19, before 6.19.13 (fixed in 6.19.13); version 4.15 only; …

Published 2026-04-24. Last modified 2026-09-18.