CVE-2026-12324: Incorrect boundary conditions in the Graphics: CanvasWebGL component

Severity: high (CVSS 7.3 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: 2026-06-16 · updated 2026-10-26
Weakness: CWE-703

Description

Incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

Affected products

Mozilla Firefox: before 140.12.0; before 152.0.0 — fixed in 140.12.0, 152.0.0
Mozilla Thunderbird: before 140.12.0; before 152.0.0 — fixed in 140.12.0, 152.0.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 140.12.0, 152.0.0; Mozilla Thunderbird 140.12.0, 152.0.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2038444
https://www.mozilla.org/security/advisories/mfsa2026-57/
https://www.mozilla.org/security/advisories/mfsa2026-58/
https://www.mozilla.org/security/advisories/mfsa2026-60/
https://www.mozilla.org/security/advisories/mfsa2026-61/

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