CVE-2025-6429
6.5
MEDIUM
CVSS 3.1
EPSS 0.43%
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 was fixed in Firefox 140, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.
How to fix CVE-2025-6429
To remediate CVE-2025-6429, upgrade the affected package to a fixed version below.
- —upgrade to 128.12.0esr-1~deb11u1 or later
- —upgrade to 1:128.12.0esr-1~deb11u1 or later
Is CVE-2025-6429 being exploited?
Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 128.12.0esr-1~deb11u1
- from 0, < 1:128.12.0esr-1~deb11u1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N |