Uninitialized Memory Flaw in Firefox’s Canvas2D Component
CVE-2026-4715

9.1CRITICAL

Key Information:

Vendor

Mozilla
Status
Firefox
Firefox Esr
Thunderbird
Vendor
CVE Published:
24 March 2026

What is CVE-2026-4715?

This vulnerability involves uninitialized memory in the Graphics: Canvas2D component of Firefox, which could potentially allow attackers to exploit memory contents. Affected versions include Firefox versions earlier than 149 and Firefox ESR versions earlier than 140.9. Users should ensure they are running updated versions to mitigate any risks.

Affected Version(s)

Firefox < 149

Firefox ESR < 140.9

Thunderbird < 149

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2018405
https://www.mozilla.org/security/advisories/mfsa2026-20/
https://www.mozilla.org/security/advisories/mfsa2026-22/

CVSS V3.1

Score:
9.1
Severity:
CRITICAL
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Jun Yang
.