Unrated severityNVD Advisory· Published Sep 29, 2026

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.

Affected products

Mozilla Corporation/Firefox Esrllm-fuzzy
Range: up to 153.4, 115.42, 140.17
Mozilla Corporation/Firefoxllm-fuzzy
Range: up to 157

Patches

Vulnerability mechanics

References

bugzilla.mozilla.org/show_bug.cginvd
www.mozilla.org/security/advisories/mfsa2026-100/nvd
www.mozilla.org/security/advisories/mfsa2026-97/nvd
www.mozilla.org/security/advisories/mfsa2026-98/nvd
www.mozilla.org/security/advisories/mfsa2026-99/nvd

News mentions

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