CVE-2026-0883: Mozilla Firefox

Medium severity, CVSS 5.3. EPSS: 0.5% chance of exploitation in the next 30 days.

Information disclosure in the Networking component. This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

Affected products

• Mozilla Firefox: before 140.7.0 (fixed in 140.7.0); before 147.0 (fixed in 147.0)
• Mozilla Thunderbird: before 140.7.0 (fixed in 140.7.0); before 147.0 (fixed in 147.0)

Published 2026-01-13. Last modified 2026-06-17.