---
id: CVE-2026-80777
title: 'futex/pi: Plug private futex exec() race'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  futex/pi: Plug private futex exec() race

  The check for private futexes whether the waiter's mm, which is stored in
  the futex_key and copied into the pi_state, is the s…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 80367ad01d93ac781b0e1df246edaf006928002f <
    fdf538b2e69653ff740e84042245018e5680cd7b
  - >-
    Linux >= 80367ad01d93ac781b0e1df246edaf006928002f <
    0478bc6bf197629fea0331d65b39eeea043c6cf0
  - >-
    Linux >= 80367ad01d93ac781b0e1df246edaf006928002f <
    d7944cee62ec6cca1c90780a766960a57d3b4bb8
  - >-
    Linux >= 80367ad01d93ac781b0e1df246edaf006928002f <
    c5f0bc9fd1cec4a00400cc727fcde03e0fde17cc
  - Linux 6.16
published: '2026-09-04'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:43:32.707Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80777'
references:
  - url: 'https://git.kernel.org/stable/c/fdf538b2e69653ff740e84042245018e5680cd7b'
  - url: 'https://git.kernel.org/stable/c/0478bc6bf197629fea0331d65b39eeea043c6cf0'
  - url: 'https://git.kernel.org/stable/c/d7944cee62ec6cca1c90780a766960a57d3b4bb8'
  - url: 'https://git.kernel.org/stable/c/c5f0bc9fd1cec4a00400cc727fcde03e0fde17cc'
tags:
  - cve.org
epss: 0.00209
epssPercentile: 0.10312
ingestedAt: '2026-10-19T10:20:54.954Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

futex/pi: Plug private futex exec() race

The check for private futexes whether the waiter's mm, which is stored in
the futex_key and copied into the pi_state, is the same as the owner's mm
is not sufficient for exec(). exec() has a gap where the mm check fails to
give the correct answer:

  exec()
  ...
    exec_release_mm()
      futex_exec_release()
        tsk::futex::exit_state = EXITING;
        cleanup_robust_list();
1)      tsk::futex::exit_state = OK;
    ...
    old_mm = tsk::mm;
2)  tsk::mm = ->mm;

Between #1 and #2 the check for the mm is wrong as that mm is about to be
swapped out and eventually freed.

Plug this gap by:

  1) Setting tsk::futex::exit_state to FUTEX_STATE_DEAD in
     futex_exec_release()

  2) Setting tsk::futex::exit_state to FUTEX_STATE_OK after
     the mm has been switched.

From a futex point of view the task is dead after it finished the robust
list cleanup up to the point where it sets the state to OK again.

## Affected

- `Linux >= 80367ad01d93ac781b0e1df246edaf006928002f < fdf538b2e69653ff740e84042245018e5680cd7b`
- `Linux >= 80367ad01d93ac781b0e1df246edaf006928002f < 0478bc6bf197629fea0331d65b39eeea043c6cf0`
- `Linux >= 80367ad01d93ac781b0e1df246edaf006928002f < d7944cee62ec6cca1c90780a766960a57d3b4bb8`
- `Linux >= 80367ad01d93ac781b0e1df246edaf006928002f < c5f0bc9fd1cec4a00400cc727fcde03e0fde17cc`
- `Linux 6.16`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.