CVE-2026-4692: Sandbox Escape via Responsive Design Mode in Firefox <149
CVE-2026-4692 Published on March 24, 2026

Sandbox escape in the Responsive Design Mode component
Sandbox escape in the Responsive Design Mode component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

NVD

Vulnerability Analysis

CVE-2026-4692 is exploitable with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
REQUIRED
Scope:
CHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
HIGH

Products Associated with CVE-2026-4692

Want to know whenever a new CVE is published for Mozilla products? stack.watch will email you.

Mozilla Firefox
 
Mozilla FireFox Extended Support Release (ESR)
 
Mozilla Thunderbird
 

Affected Versions

Mozilla Firefox: Mozilla Thunderbird:

Exploit Probability

EPSS
0.03%
Percentile
7.07%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.