SecuriTricks - CVE-2025-6429

Description

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 affects Firefox < 140 and Firefox ESR < 128.12.

Product(s) Impacted

Vendor	Product	Versions
Mozilla	Firefox Firefox Esr	<140 <128.12

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-116

Improper Encoding or Escaping of Output

The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	mozilla	firefox	<140	/	/	/	/	/	/	/
a	mozilla	firefox_esr	<128.12	/	/	/	/	/	/	/

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1970658

https://www.mozilla.org/security/advisories/mfsa2025-51/

https://www.mozilla.org/security/advisories/mfsa2025-53/

CVSS Score

6.5 / 10

CVSS Data - 3.1

Attack Vector: NETWORK
Attack Complexity: LOW
Privileges Required: NONE
Scope: UNCHANGED
Confidentiality Impact: NONE
Integrity Impact: HIGH
Availability Impact: NONE

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

View Vector String

Timeline

Published: June 24, 2025, 1:15 p.m.
Last Modified: June 25, 2025, 3:15 p.m.

Status : Received

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

security@mozilla.org

CVE-2025-6429