CVE-2026-31554: futex: Require sys_futex_requeue() to have identical flags

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-24 · updated 2026-10-19
Weakness: CWE-416

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.

Affected products

Linux kernel: from 6.7.1 before 6.12.80; from 6.13 before 6.18.21; from 6.19 before 6.19.11; 6.7, 7.0-rc1, 7.0-rc2, 7.0-rc3, 7.0-rc4, 7.0-rc5 (+2) — fixed in 6.12.80, 6.18.21, 6.19.11

How to fix

Upgrade to a fixed version: Linux kernel 6.12.80, 6.18.21, 6.19.11. Check the vendor advisory for mitigations.

References

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