CVE-2026-2783: Mozilla Firefox

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Information disclosure due to JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Affected products

• Mozilla Firefox: before 140.8.0 (fixed in 140.8.0); before 148.0 (fixed in 148.0)
• Mozilla Thunderbird: before 140.8.0 (fixed in 140.8.0); before 148.0 (fixed in 148.0)

Published 2026-02-24. Last modified 2026-06-17.