What is CVE-2026-8952?

CVE-2026-8952 is a high-severity vulnerability in Mozilla Firefox, classified under Improper Privilege Management. CVSS score: 8.8/10. Published 2026-05-19.

How severe is CVE-2026-8952?

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

Privilege escalation in Mozilla Firefox

CVE-2026-8952

Privilege escalation in the Application Update component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

Vulnerability class: Privilege Escalation

EPSS: 0.000 (12.8th percentile) — read the EPSS interpretation.

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 151
Mozilla Thunderbird — versions 151

Weakness classification (CWE)

CWE-269 — Improper Privilege Management

References

security@mozilla.org (Permissions Required)
security@mozilla.org (Vendor Advisory)
security@mozilla.org (Vendor Advisory)

Frequently asked questions

What is CVE-2026-8952?: CVE-2026-8952 is a high-severity vulnerability in Mozilla Firefox, classified under Improper Privilege Management. CVSS score: 8.8/10. Published 2026-05-19.
How severe is CVE-2026-8952?: High severity. CVSS v3 base score is 8.8 out of 10.