Memory Safety Issue in Firefox by Mozilla
CVE-2026-12310

7.5HIGH

Key Information:

Vendor

Mozilla
Status
Firefox
Thunderbird
Vendor
CVE Published:
16 June 2026

What is CVE-2026-12310?

A memory safety vulnerability has been identified in Firefox that can potentially lead to unintended behaviors and security risks. This issue was addressed in Firefox version 152 and its Extended Support Release (ESR) version 140.12, ensuring enhanced protection for users against potential exploits related to this flaw. Users are encouraged to update their Firefox installations to mitigate the risks associated with this vulnerability.

Affected Version(s)

Firefox 140.12

Firefox 152

Thunderbird 140.12

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2039707
https://www.mozilla.org/security/advisories/mfsa2026-57/
https://www.mozilla.org/security/advisories/mfsa2026-58/

CVSS V3.1

Score:
7.5
Severity:
HIGH
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

Carl Pearson
.