Vulnerability · Published Apr 12, 2026 · Assigned by mitre
CVE-2026-40393
High 8.1
In plain English
A high-severity out-of-bounds write in Mesa from mesa3d. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.4%top 62.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | mesa | 22.3.6-1+deb12u2 | DEBIAN-CVE-2026-40393 |
| Debian:13 | mesa | 25.0.7-2+deb13u1 | DEBIAN-CVE-2026-40393 |
| Debian:14 | mesa | 26.0.1-1 | DEBIAN-CVE-2026-40393 |
| Ubuntu:22.04:LTS | mesa | 23.2.1-1ubuntu3.1~22.04.4 | USN-8427-1 |
| Ubuntu:22.04:LTS | mesa | 23.2.1-1ubuntu3.1~22.04.4 | UBUNTU-CVE-2026-40393 |
| Ubuntu:24.04:LTS | mesa | 25.2.8-0ubuntu0.24.04.2 | USN-8427-1 |
| Ubuntu:24.04:LTS | mesa | 25.2.8-0ubuntu0.24.04.2 | UBUNTU-CVE-2026-40393 |
| Ubuntu:25.10 | mesa | 25.2.8-0ubuntu0.25.10.2 | UBUNTU-CVE-2026-40393 |
| Ubuntu:25.10 | mesa | 25.2.8-0ubuntu0.25.10.2 | USN-8427-1 |
Affected products (as reported)
Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H