CVE-2026-8957

⚠️ high

Summary

Privilege escalation in the Enterprise Policies component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVSS Score

8.8

High

EPSS Score

0.0

Exploit Probability

Published Date

2026-05-19

First Seen: 2026-05-20

📊 Relative Risk Intelligence

This CVE is High Risk - more severe than 80.8% of all 355,915 vulnerabilities in our database.

#68,271

Top 25% most severe

Severity Percentile

🎯 CISA SSVC Assessment Updated: May 20, 2026

🔍 Exploitation Status

None

No known exploits

⚙️ Automatable

Requires human interaction

💥 Technical Impact

Total

Complete system compromise possible

🏆 Discovered By

Mateusz Dobrzyński

SSVC data provided by CISA

Last Modified 2026-05-20

Source NVD 🔗

CVSS Vector 3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE IDs (Weakness Types)

CWE-269

📦 Affected Products 4

Vendor	Product	Status	Affected Versions
mozilla	firefox	Affected	< 140.11.0
mozilla	firefox	Affected	< 151.0.0
mozilla	thunderbird	Affected	< 140.11
mozilla	thunderbird	Affected	< 151.0.0

🔗 References 5

https://bugzilla.mozilla.org/show_bug.cgi?id=2033850

Permissions Required

https://www.mozilla.org/security/advisories/mfsa2026...

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2026...

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2026...

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2026...

Vendor Advisory

🔗 Related CVEs 6

CVE ID	Severity	CVSS	EPSS	Summary	Published
CVE-2026-84118	🔶 medium	5.4	0.2	Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderb...	2026-09-01
CVE-2026-84119	⛔ critical	9.6	0.3	Sandbox escape due to use-after-free in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Fire...	2026-09-01
CVE-2026-84120	🔶 medium	5.4	0.2	Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ES...	2026-09-01
CVE-2026-84121	⛔ critical	9.6	0.3	Sandbox escape due to use-after-free in the DOM: Security component. This vulnerability was fixed in Firefox 155, Firefo...	2026-09-01
CVE-2026-84122	🔶 medium	5.4	0.2	Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, Firefox ES...	2026-09-01
CVE-2026-84123	⚠️ high	8.8	0.2	Privilege escalation due to use-after-free in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 15...	2026-09-01

These CVEs affect the same products