Vulnerability in Mozilla Firefox
CVE-2026-92050
Sandbox escape due to race condition in the XPConnect component. This vulnerability was fixed in Firefox 156 and Thunderbird 156.
Vulnerability class: Race Condition
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (35.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 35.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: -0.000
Affected products
Weakness classification (CWE)
References
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required)
- www.mozilla.org/security/advisories/mfsa2026-90/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2026-94/ (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-92050?
- CVE-2026-92050 is a critical-severity vulnerability in Mozilla Firefox, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 9.1/10. Published 2026-09-15.
- How severe is CVE-2026-92050?
- Critical severity. CVSS v3 base score is 9.1 out of 10.