Privilege Escalation Vulnerability in Firefox by Mozilla
CVE-2026-16401

8.8HIGH

Key Information:

Vendor

Mozilla
Status
Firefox
Thunderbird
Vendor
CVE Published:
21 July 2026

What is CVE-2026-16401?

A vulnerability exists in the Data Loss Prevention component of Firefox that allows for privilege escalation. This security flaw could potentially enable unauthorized users to gain elevated access, compromising sensitive data and functionality. Mozilla has addressed this issue in Firefox version 153, ensuring enhanced protection against such exploits. Users are advised to update to the latest version to mitigate any associated risks.

Affected Version(s)

Firefox 153

Thunderbird 153

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2052565
https://www.mozilla.org/security/advisories/mfsa2026-68/
https://www.mozilla.org/security/advisories/mfsa2026-71/

CVSS V3.1

Score:
8.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Brian Carpenter
.