CVE-2026-100803

Description

Same-origin policy bypass in the WebExtensions component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=2057988
• https://www.mozilla.org/security/advisories/mfsa2026-100/
• https://www.mozilla.org/security/advisories/mfsa2026-97/
• https://www.mozilla.org/security/advisories/mfsa2026-98/
• https://www.mozilla.org/security/advisories/mfsa2026-99/