Mitigation Bypass in Firefox Networking Component
CVE-2026-16406

9.1CRITICAL

Key Information:

Vendor

Mozilla
Status
Firefox
Thunderbird
Vendor
CVE Published:
21 July 2026

What is CVE-2026-16406?

A mitigation bypass vulnerability has been identified in the networking component of Firefox, which could potentially allow attackers to circumvent established security measures. This issue has been addressed in Firefox 153, ensuring enhanced protection within the application’s networking functions. Users are encouraged to update to the latest version to mitigate risks associated with this vulnerability.

Affected Version(s)

Firefox 153

Thunderbird 153

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2040382
https://www.mozilla.org/security/advisories/mfsa2026-68/
https://www.mozilla.org/security/advisories/mfsa2026-71/

CVSS V3.1

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

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Rintaro Kawasugi
.