Alt-Svc ALPN validation failure when redirected

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-0239
StatePUBLISHED
Assignermozilla
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-01-07 16:15:38 UTC
Updated2026-04-13 15:16:32 UTC
DescriptionWhen 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.

Risk And Classification

Primary CVSS: v3.1 4 MEDIUM from ADP

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Problem Types: CWE-295 | CWE-295 CWE-295 Improper Certificate Validation

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED4MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary4MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Mozilla Firefox All All All All
Application Mozilla Firefox All All All All
Application Mozilla Thunderbird All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mozilla Firefox unaffected 128.6 128.* rpm Not specified
CNA Mozilla Firefox unaffected 134 * rpm Not specified
CNA Mozilla Thunderbird unaffected 128.6 128.* rpm Not specified
CNA Mozilla Thunderbird unaffected 134 * rpm Not specified

References

ReferenceSourceLinkTags
bugzilla.mozilla.org/show_bug.cgi [email protected] bugzilla.mozilla.org Issue Tracking, Permissions Required
www.mozilla.org/security/advisories/mfsa2025-02 [email protected] www.mozilla.org Vendor Advisory
www.mozilla.org/security/advisories/mfsa2025-01 [email protected] www.mozilla.org Vendor Advisory
www.mozilla.org/security/advisories/mfsa2025-05 [email protected] www.mozilla.org Vendor Advisory
www.mozilla.org/security/advisories/mfsa2025-04 [email protected] www.mozilla.org Vendor Advisory
lists.debian.org/debian-lts-announce/2025/01/msg00004.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Paul Gerste (en)

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