Vulnerability Description
Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 147, Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.
CVSS Score
8.1
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 115.32.0 |
| Mozilla | Thunderbird | < 140.7.0 |
Related Weaknesses (CWE)
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1999257Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-01/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-02/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-03/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-04/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-05/Vendor Advisory
FAQ
What is CVE-2026-0877?
CVE-2026-0877 is a vulnerability with a CVSS score of 8.1 (HIGH). Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 147, Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.
How severe is CVE-2026-0877?
CVE-2026-0877 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-0877?
Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox, Mozilla Thunderbird.