What is CVE-2026-12289?

CVE-2026-12289 is a high-severity vulnerability in Mozilla Firefox, classified under Improper Privilege Management. CVSS score: 8.8/10. Published 2026-06-16.

How severe is CVE-2026-12289?

High severity. CVSS v3 base score is 8.8 out of 10.

Privilege escalation in Mozilla Firefox

CVE-2026-12289

Privilege escalation in the Graphics: WebRender component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

Vulnerability class: Privilege Escalation

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

Affected products

Mozilla Firefox — versions 115.37, 140.12, 152
Mozilla Thunderbird — versions 140.12, 152

Weakness classification (CWE)

CWE-269 — Improper Privilege Management

References

security@mozilla.org
security@mozilla.org
security@mozilla.org
security@mozilla.org
security@mozilla.org
security@mozilla.org

Frequently asked questions

What is CVE-2026-12289?: CVE-2026-12289 is a high-severity vulnerability in Mozilla Firefox, classified under Improper Privilege Management. CVSS score: 8.8/10. Published 2026-06-16.
How severe is CVE-2026-12289?: High severity. CVSS v3 base score is 8.8 out of 10.