CVE-2025-0239

Severity CVSS v4.0:

Pending analysis

Type:

CWE-295 Improper Certificate Validation

Publication date:

07/01/2025

Last modified:

13/04/2026

Description

When using Alt-Svc, ALPN did not properly validate certificates when the original server is redirecting to an insecure site. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.

Impact

Vector 3.x

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS v3.1 Severity and Metrics:

Base Score: 4.00 MEDIUM
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): Low
Availability (A): None

Base Score 3.x

4.00

Severity 3.x

MEDIUM

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:a:mozilla:firefox:::::esr:::*		128.6.0 (excluding)
cpe:2.3:a:mozilla:firefox::::::::		134.0 (excluding)
cpe:2.3:a:mozilla:thunderbird::::::::		128.6.0 (excluding)
cpe:2.3:a:mozilla:thunderbird::::::::	129.0 (including)	134.0 (excluding)

To consult the complete list of CPE names with products and versions, see this page

CVE-2025-0239

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools