xfrm: hold dev ref until after transport_finish NF_HOOK
CVE-2026-31663 · published 24 Apr 2026
How serious is it
- Severity: high, CVSS score 7.8 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-31663?
Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.
Who is affected
- Linux Linux: acf568ee859f098279eadf551612f103afdacb4e to < 94439cbe478b53f92223da9aae95fffb28623c3f, acf568ee859f098279eadf551612f103afdacb4e to < 4236c30b437b80f673b9e08c8fae38b8d471ac9e, acf568ee859f098279eadf551612f103afdacb4e to < 0f451b43c88bf2b9c038b414be580efee42e031b, acf568ee859f098279eadf551612f103afdacb4e to < 5002beda5cac69d522dc54da0d5d463ed9c963d2
- Linux Linux: 4.15
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
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.
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/94439cbe478b53f92223da9aae95fffb28623c3f
- git.kernel.org/stable/c/4236c30b437b80f673b9e08c8fae38b8d471ac9e
- git.kernel.org/stable/c/0f451b43c88bf2b9c038b414be580efee42e031b
- git.kernel.org/stable/c/5002beda5cac69d522dc54da0d5d463ed9c963d2
- git.kernel.org/stable/c/1c428b03840094410c5fb6a5db30640486bbbfcb
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON