CVE-2026-12303: Mozilla Firefox

Medium severity, CVSS 4.3. EPSS: 0.2% chance of exploitation in the next 30 days.

Information disclosure due to incorrect boundary conditions in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 152 and Thunderbird 152.

Affected products

• Mozilla Firefox: before 152.0 (fixed in 152.0)
• Mozilla Thunderbird: before 152.0.0 (fixed in 152.0.0)

Published 2026-06-16. Last modified 2026-06-17.