Certificate Validation Flaw in Mozilla Products Affects Firefox and Thunderbird
CVE-2025-0239

4MEDIUM

Key Information:

Vendor
Mozilla
Status
Firefox
Firefox Esr
Thunderbird
Thunderbird Esr
Vendor
CVE Published:
7 January 2025

Summary

A vulnerability affecting Mozilla's Firefox and Thunderbird involves improper validation of certificates triggered by Alt-Svc and ALPN when redirecting from a secure to an insecure server. This flaw potentially exposes users to risks as it might allow malicious entities to intercept or manipulate data without being detected. Users of affected versions are advised to prioritize upgrades to protect themselves against potential exploitation.

Affected Version(s)

Firefox < 134

Firefox ESR < 128.6

Thunderbird < 134

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1929156
https://www.mozilla.org/security/advisories/mfsa2025-01/
https://www.mozilla.org/security/advisories/mfsa2025-02/

CVSS V3.1

Score:
4
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

Credit

Paul Gerste
.