CVE-2026-100809

Same-origin policy bypass in the DevTools component

Published Sep 29, 2026 CVSS 3.1 · 8.1 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4814-1 firefox-esr security update
Debian DSA Debian DSA DSA-6533-1 firefox-esr security update
History
Type Values Removed Values Added
First Time appeared Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
Vendors & Products Mozilla thunderbird
Type Values Removed Values Added
Weaknesses CWE-284
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Weaknesses CWE-346
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N'}

Type Values Removed Values Added
Weaknesses CWE-284
Type Values Removed Values Added
Weaknesses CWE-285
Type Values Removed Values Added
Description Same-origin policy bypass in the DevTools component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, and Firefox 157. 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.
References
Type Values Removed Values Added
Description Same-origin policy bypass in the DevTools component. This vulnerability was fixed in Firefox ESR 153.4 and Firefox 157. Same-origin policy bypass in the DevTools component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, and Firefox 157.
References
Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox
Type Values Removed Values Added
Weaknesses CWE-285
Type Values Removed Values Added
Description Same-origin policy bypass in the DevTools component. This vulnerability was fixed in Firefox ESR 153.4 and Firefox 157.
Title Same-origin policy bypass in the DevTools component
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mozilla
Published
Updated
Oct 1, 2026, 3:31 PM
Reserved
Sep 26, 2026, 7:18 PM
Status
Analyzed
Published
Sep 29, 2026, 1:17 PM
Modified
Oct 5, 2026, 2:30 PM