Integer Overflow Vulnerability in NSS Libraries Affects Firefox
CVE-2026-16389

9.8CRITICAL

Key Information:

Vendor

Mozilla
Status
Firefox
Thunderbird
Vendor
CVE Published:
21 July 2026

What is CVE-2026-16389?

An integer overflow vulnerability occurs within the Libraries component in the NSS (Network Security Services) used by Mozilla's Firefox browser. This issue arises from incorrect boundary conditions, potentially allowing for unauthorized actions or exploit attempts. Mozilla has addressed this vulnerability in Firefox version 153, enhancing security and stability for users.

Affected Version(s)

Firefox 153

Thunderbird 153

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2043887
https://www.mozilla.org/security/advisories/mfsa2026-68/
https://www.mozilla.org/security/advisories/mfsa2026-71/

CVSS V3.1

Score:
9.8
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

Tomoya Nakanishi
.