CVE-2026-100816

Site isolation issue in the DOM: Networking component

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

Description

Site isolation issue in the DOM: Networking 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=2068648
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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