Memory Safety Vulnerability in Firefox by Mozilla
CVE-2026-12312

7.5HIGH

Key Information:

Vendor

Mozilla
Status
Firefox
Thunderbird
Vendor
CVE Published:
16 June 2026

What is CVE-2026-12312?

A memory safety issue was identified in Firefox that could potentially allow for unexpected behavior or exploitation of the software. This vulnerability affects users of Firefox 152 and Firefox ESR 140.12, prompting users to update to the latest versions to ensure their security. Mozilla has addressed this issue in the respective releases, enhancing overall stability and user safety.

Affected Version(s)

Firefox 140.12

Firefox 152

Thunderbird 140.12

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2040383
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

Rintaro Kawasugi
.