Sandbox Escape Vulnerability in Firefox's Canvas2D Component
CVE-2026-4725

9.3CRITICAL

Key Information:

Vendor

Mozilla
Status
Firefox
Thunderbird
Vendor
CVE Published:
24 March 2026

What is CVE-2026-4725?

A vulnerability in the Graphics: Canvas2D component of Firefox allows for a sandbox escape resulting from a use-after-free condition. This flaw may permit malicious web content to execute code outside its intended security boundary, compromising the integrity and confidentiality of affected environments. Users of Firefox versions prior to 149 are at risk, necessitating prompt updates to mitigate potential exploitation.

Affected Version(s)

Firefox < 149

Thunderbird < 149

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2017108
https://www.mozilla.org/security/advisories/mfsa2026-20/
https://www.mozilla.org/security/advisories/mfsa2026-23/

CVSS V3.1

Score:
9.3
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Jun Yang
.