Vulnerability Description
Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 115.40.0 |
| Mozilla | Thunderbird | < 140.15.0 |
Related Weaknesses (CWE)
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2058911Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-82/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-83/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-84/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-85/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-86/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-87/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-88/Vendor Advisory
FAQ
What is CVE-2026-84120?
CVE-2026-84120 is a vulnerability with a CVSS score of 5.4 (MEDIUM). Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbir...
How severe is CVE-2026-84120?
CVE-2026-84120 has been rated MEDIUM with a CVSS base score of 5.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-84120?
Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox, Mozilla Thunderbird.