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, Firefox ESR < 128.12, Thunderbird < 140, and Thunderbird < 128.12.

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Vendors Products
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Rhel Eus Subscribe
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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4231-1 firefox-esr security update
Debian DLA Debian DLA DLA-4239-1 thunderbird security update
Debian DSA Debian DSA DSA-5950-1 firefox-esr security update
Debian DSA Debian DSA DSA-5959-1 thunderbird security update
EUVD EUVD EUVD-2025-21378 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, Firefox ESR < 128.12, Thunderbird < 140, and Thunderbird < 128.12.
Ubuntu USN Ubuntu USN USN-7663-1 Thunderbird vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Mon, 03 Nov 2025 20:30:00 +0000


Thu, 30 Oct 2025 16:30:00 +0000

Type Values Removed Values Added
Title firefox: thunderbird: Incorrect parsing of URLs could have allowed embedding of youtube.com Incorrect parsing of URLs could have allowed embedding of youtube.com

Wed, 16 Jul 2025 13:45:00 +0000

Type Values Removed Values Added
Metrics epss

{'score': 0.00035}

epss

{'score': 0.00062}


Tue, 15 Jul 2025 13:45:00 +0000

Type Values Removed Values Added
Metrics epss

{'score': 0.00031}

epss

{'score': 0.00035}


Mon, 14 Jul 2025 18:45:00 +0000

Type Values Removed Values Added
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. 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, Firefox ESR < 128.12, Thunderbird < 140, and Thunderbird < 128.12.
References

Fri, 04 Jul 2025 02:30:00 +0000

Type Values Removed Values Added
Title firefox: Incorrect parsing of URLs could have allowed embedding of youtube.com firefox: thunderbird: Incorrect parsing of URLs could have allowed embedding of youtube.com

Thu, 03 Jul 2025 17:00:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
Vendors & Products Mozilla
Mozilla firefox

Wed, 02 Jul 2025 14:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat rhel Aus
Redhat rhel E4s
Redhat rhel Els
Redhat rhel Eus
Redhat rhel Tus
CPEs cpe:/a:redhat:enterprise_linux:9
cpe:/a:redhat:rhel_aus:8.2
cpe:/a:redhat:rhel_aus:8.4
cpe:/a:redhat:rhel_aus:8.6
cpe:/a:redhat:rhel_e4s:8.6
cpe:/a:redhat:rhel_e4s:8.8
cpe:/a:redhat:rhel_e4s:9.0
cpe:/a:redhat:rhel_e4s:9.2
cpe:/a:redhat:rhel_eus:9.4
cpe:/a:redhat:rhel_tus:8.6
cpe:/a:redhat:rhel_tus:8.8
cpe:/o:redhat:enterprise_linux:10.0
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Aus
Redhat rhel E4s
Redhat rhel Els
Redhat rhel Eus
Redhat rhel Tus

Wed, 02 Jul 2025 02:30:00 +0000

Type Values Removed Values Added
First Time appeared Redhat
Redhat enterprise Linux
CPEs cpe:/a:redhat:enterprise_linux:8
Vendors & Products Redhat
Redhat enterprise Linux

Thu, 26 Jun 2025 02:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-706
References

Wed, 25 Jun 2025 15:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-116
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N'}


Wed, 25 Jun 2025 00:30:00 +0000

Type Values Removed Values Added
Title firefox: Incorrect parsing of URLs could have allowed embedding of youtube.com
References
Metrics threat_severity

None

cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

threat_severity

Moderate


Tue, 24 Jun 2025 12:45:00 +0000

Type Values Removed Values Added
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.
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2025-11-03T20:07:03.248Z

Reserved: 2025-06-20T14:51:34.184Z

Link: CVE-2025-6429

cve-icon Vulnrichment

Updated: 2025-11-03T20:07:03.248Z

cve-icon NVD

Status : Modified

Published: 2025-06-24T13:15:23.877

Modified: 2025-11-03T20:19:19.097

Link: CVE-2025-6429

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-06-24T12:28:00Z

Links: CVE-2025-6429 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-07-06T22:16:30Z

Weaknesses