CVEvulnerability
CVE-2026-84121
9.6 CRITICAL
Official page ↗
- Status
- Analyzed
- Published
- 2026-09-01
- Last modified
- 2026-09-02
- Assigner
- [email protected]
- CVSS 3.1 (134c704f-9b21-4f2e-91b3-4a467353bcc0)
- 9.6 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
- Weaknesses
- CWE-416
Description
Sandbox escape due to use-after-free in the DOM: Security 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.
Affected configurations
• mozilla firefox (< 115.40.0)
• mozilla firefox (>= 116.0 < 140.15.0)
• mozilla firefox (>= 141.0.0 < 153.2.0)
• mozilla firefox (>= 154.0.0 < 155.0.0)
• mozilla thunderbird (< 140.15.0)
• mozilla thunderbird (>= 141.0 < 153.2.0)
• mozilla thunderbird (>= 154.0 < 155.0)
Related
Weakness · CWE (1)
- CWE-416 Use After Free weakness
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2059018 Permissions 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