Memory Safety Bug in Firefox Affects Mozilla Products
CVE-2026-12309

Currently unrated

Key Information:

Vendor: Mozilla
Status: Firefox
Vendor: CVE Published:; 16 June 2026

What is CVE-2026-12309?

A memory safety issue has been identified and resolved in Firefox, affecting versions 152 and Firefox ESR 140.12. This security flaw could allow an attacker to exploit the browser, potentially leading to unauthorized access and system instability. Users are strongly encouraged to update to the latest versions to ensure protection against these vulnerabilities.

Affected Version(s)

Firefox 140.12

Firefox 152

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2038476

https://www.mozilla.org/security/advisories/mfsa2026-57/

https://www.mozilla.org/security/advisories/mfsa2026-58/

Download the Critical Vulnerability Management Cheat Sheet

Timeline

Vulnerability published
Jun 16, 2026
Vulnerability Reserved
Jun 15, 2026

Credit

Yaqoub Aldurayhim

CVE-2026-12309 Data

JSON