CVE-2026-100809

Same-origin policy bypass in the DevTools component

State: Published
Severity: 8.1 High
Published: Sep 29, 2026
Updated: Oct 1, 2026
Reserved: Sep 26, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	8.1 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N	CISA-ADP

Weaknesses

CWE-346 Origin Validation Error

Affected Products

Product	Versions
FirefoxMozilla	153.4 through 153.*Not affected 157 and laterNot affected
ThunderbirdMozilla	153.4 through 153.*Not affected 157 and laterNot affected

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2063658
https://www.mozilla.org/security/advisories/mfsa2026-100/
https://www.mozilla.org/security/advisories/mfsa2026-101/
https://www.mozilla.org/security/advisories/mfsa2026-103/
https://www.mozilla.org/security/advisories/mfsa2026-97/

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