CVE-2026-109778: Vulnerability in Mozilla Firefox
Description
Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
CVSS v3.1
Score 8.8high
Affected software
Mozilla
Firefox
Mozilla
Thunderbird
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves privilege escalation within the WebExtensions component of Mozilla Firefox. It affects versions prior to Firefox 158 and Firefox ESR 153.5. Mozilla has published advisories MFSA2026-106 and MFSA2026-108 addressing this issue and providing fixes.
Potential Impact
Successful exploitation of this vulnerability could allow an attacker to escalate privileges within the Firefox browser, potentially leading to unauthorized actions or access within the browser context. There are no known exploits in the wild at this time.
Mitigation Recommendations
Users should update Firefox to version 158 or later, or Firefox ESR 153.5 or later, where this vulnerability has been fixed. Refer to Mozilla's security advisories MFSA2026-106 and MFSA2026-108 for detailed remediation information.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-10-13T00:49:10.870Z
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-106/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-108/","vendor":"Mozilla"}]
Threat ID: 6ace2c512cdf04f65661d578
Added to database: 10/13/2026, 13:04:17 UTC
Last enriched: 10/13/2026, 13:19:01 UTC
Last updated: 10/13/2026, 18:57:33 UTC
Views: 7
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