CVE-2026-100811

CRITICAL CVSS 3.1: 9.6 EPSS 0.26%
Updated Oct 05, 2026
Mozilla
Parameter Value
CVSS 9.6 (CRITICAL)
Affected Versions 141.0 — 157.0.0
Fixed In 140.17.0
Type CWE-416 (Use After Free)
Vendor Mozilla
Public PoC No

Sandbox escape due to use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
Required
User action required

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Weakness Type (CWE)

Vulnerable Products 6

Configuration From (including) Up to (excluding)
Mozilla Firefox
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
— 140.17.0
Mozilla Firefox
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
141.0 153.4.0
Mozilla Firefox
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
154.0.0 157.0.0
Mozilla Thunderbird
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
— 140.17.0
Mozilla Thunderbird
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
141.0 153.4.0
Mozilla Thunderbird
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
154.0 157.0