CVE-2026-100766
Information disclosure in the Networking: JAR component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
- Published Sep 29, 2026
- CVSS 4.3 medium
- 0.3% chance of exploitation in the next 30 days (EPSS)
- A fix is available