CVE-2025-6429

Firefox could have incorrectly parsed a URL and rewritten it to the youtube.com domain when parsing the URL specified in an `embed` tag. This could have bypassed website security checks that restricted which domains users were allowed to embed. This vulnerability was fixed in Firefox 140, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.

CVSS v3 6.5 MEDIUM

6.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://bugzilla.mozilla.org/show_bug.cgi?id=1970658	Permissions Required
https://www.mozilla.org/security/advisories/mfsa2025-51/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-53/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-54/
https://www.mozilla.org/security/advisories/mfsa2025-55/
https://lists.debian.org/debian-lts-announce/2025/06/msg00029.html
https://lists.debian.org/debian-lts-announce/2025/07/msg00002.html

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:mozilla:firefox:::::esr:::*
	cpe:2.3:a:mozilla:firefox:::::-:::*

History

No history.

Information

Published : 2025-06-24 13:15

Updated : 2026-06-17 10:01

NVD link : CVE-2025-6429

Mitre link : CVE-2025-6429

CVE.ORG link : CVE-2025-6429

JSON object : View

Products Affected

mozilla

firefox

CWE

CWE-116

Improper Encoding or Escaping of Output

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