---
id: CVE-2026-40393
title: >-
  In Mesa before 25.3.6 and 26 before 26.0.1, out-of-bounds memory access can
  occur in WebGPU because the amount of to-be-allocated data depends on an
  untrusted party, and is then used for alloca.
summary: >-
  In Mesa before 25.3.6 and 26 before 26.0.1, out-of-bounds memory access can
  occur in WebGPU because the amount of to-be-allocated data depends on an
  untrusted party, and is then used for alloca.
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-787
vendor: mesa3d
product: mesa
affected:
  - mesa < 25.3.6
  - mesa = 26.0.0
patched:
  - mesa 25.3.6
published: '2026-04-12'
updated: '2026-07-13'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-40393'
references:
  - url: 'https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/39866'
    label: cve@mitre.org
  - url: 'https://lists.freedesktop.org/archives/mesa-dev/2026-February/226597.html'
    label: cve@mitre.org
  - url: 'https://lists.debian.org/debian-lts-announce/2026/07/msg00021.html'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00615
epssPercentile: 0.47141
ingestedAt: '2026-07-13T10:25:38.705Z'
---

## Overview

In Mesa before 25.3.6 and 26 before 26.0.1, out-of-bounds memory access can occur in WebGPU because the amount of to-be-allocated data depends on an untrusted party, and is then used for alloca.

## Affected

- `mesa < 25.3.6`
- `mesa = 26.0.0`

## Remediation

Upgrade past the affected range:

- `mesa 25.3.6`