CVE-2025-0239

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 134 Firefox ESR versions prior to 128.6 Thunderbird versions prior to 134 Thunderbird versions prior to 128.6

Description The issue arises when using Alt-Svc, as ALPN fails to properly validate certificates in scenarios where the original server redirects to an insecure site.

Recommendations For Firefox versions prior to 134, update to version 134 or later. For Firefox ESR versions prior to 128.6, update to version 128.6 or later. For Thunderbird versions prior to 134, update to version 134 or later. For Thunderbird versions prior to 128.6, update to version 128.6 or later.