CVE-2026-100809
Same-origin policy bypass in the DevTools component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
- Published Sep 29, 2026
- CVSS 8.1 high
- 0.2% chance of exploitation in the next 30 days (EPSS)
- A fix is available