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 81.1% of all 326,604 vulnerabilities in our database.

#61,754

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-2026-10701	⚠️ high	7.5	0.0	Incorrect boundary conditions in the Graphics: Text component. This vulnerability was fixed in Firefox 151.0.3.	2026-06-02
CVE-2026-10702	🔶 medium	4.3	0.0	JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 151.0.3.	2026-06-02
CVE-2026-9308	🔶 medium	5.4	0.0	Firefox for iOS Reader View replaced page content in its HTML template before replacing other internal placeholders. A m...	2026-06-01
CVE-2026-9309	🔶 medium	5.4	0.0	Firefox for iOS Reader View did not properly escape HTML tags in JSON-LD metadata. A malicious page could inject markup ...	2026-06-01
CVE-2026-9078	🔶 medium	5.4	0.0	Firefox for iOS displayed specially crafted right-to-left (RTL) and internationalized domain names (IDNs) incorrectly in...	2026-05-25
CVE-2026-8945	⚠️ high	7.5	0.1	Sandbox escape in Firefox and Firefox Focus for Android. This vulnerability was fixed in Firefox 151.	2026-05-19

These CVEs affect the same products