CVE-2026-8959
⛔ criticalSummary
Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
CVSS Score
9.6
Critical
EPSS Score
-
Published Date
2026-05-19
First Seen: 2026-05-20
📊 Relative Risk Intelligence
This CVE is Very High Risk - more severe than 90.2% of all 321,566 vulnerabilities in our database.
#31,564
Top 10% most severe
Severity Percentile
🎯 CISA SSVC Assessment Updated: May 19, 2026
🔍 Exploitation Status
None
No known exploits
⚙️ Automatable
NO
Requires human interaction
💥 Technical Impact
Total
Complete system compromise possible
🏆 Discovered By
Ameen Basha M K
SSVC data provided by
CISA
Last Modified
2026-05-19
Source
NVD 🔗
CVSS Vector 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H