CVE-2025-6429CWE-116

CVE-2025-6429

Medium · published June 24, 2025

CVSS v3.1
6.5
EPSS
0%
Percentile
28.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00355 · 28.0th percentile
Weakness
CWE-116 · Improper Encoding or Escaping of Output
Published
2025-06-24T17:15Z
Affected products (2)
ProductVersionsFixed in
mozilla/firefox< 128.12.0128.12.0
mozilla/firefox< 140.0140.0
References (7)
https://bugzilla.mozilla.org/show_bug.cgi?id=1970658 · [email protected]https://www.mozilla.org/security/advisories/mfsa2025-51/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2025-53/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2025-54/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2025-55/ · [email protected]https://lists.debian.org/debian-lts-announce/2025/06/msg00029.html · af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2025/07/msg00002.html · af854a3a-2127-422b-91ae-364da2661108
EPSS history
Timeline
  • 24 JUN 12:28Z
    Incorrect parsing of URLs could have allowed embedding of youtube.com
    cvelistv5