Vulnerability Description
Mitigation bypass in the PDF Viewer component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
CVSS Score
9.8
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 140.13.0 |
| Mozilla | Thunderbird | < 140.13.0 |
Related Weaknesses (CWE)
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2037770Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-68/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-70/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-71/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-72/Vendor Advisory
FAQ
What is CVE-2026-16377?
CVE-2026-16377 is a vulnerability with a CVSS score of 9.8 (CRITICAL). Mitigation bypass in the PDF Viewer component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
How severe is CVE-2026-16377?
CVE-2026-16377 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-16377?
Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox, Mozilla Thunderbird.