| Name | 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 was fixed in Firefox 140, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| References | DLA-4231-1, DLA-4239-1, DSA-5950-1, DSA-5959-1 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| firefox (PTS) | sid | 150.0.1-1 | fixed |
| firefox-esr (PTS) | bullseye | 115.14.0esr-1~deb11u1 | vulnerable |
| bullseye (security) | 140.10.1esr-1~deb11u1 | fixed | |
| bookworm | 128.14.0esr-1~deb12u1 | fixed | |
| bookworm (security) | 140.10.1esr-1~deb12u1 | fixed | |
| trixie | 140.8.0esr-1~deb13u1 | fixed | |
| trixie (security) | 140.10.1esr-1~deb13u1 | fixed | |
| forky | 140.10.0esr-1 | fixed | |
| sid | 140.10.1esr-1 | fixed | |
| thunderbird (PTS) | bullseye | 1:115.12.0-1~deb11u1 | vulnerable |
| bullseye (security) | 1:140.10.1esr-1~deb11u1 | fixed | |
| bookworm | 1:140.6.0esr-1~deb12u1 | fixed | |
| bookworm (security) | 1:140.10.1esr-1~deb12u1 | fixed | |
| trixie | 1:140.8.0esr-1~deb13u1 | fixed | |
| trixie (security) | 1:140.10.1esr-1~deb13u1 | fixed | |
| forky | 1:140.10.0esr-1 | fixed | |
| sid | 1:140.10.1esr-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| firefox | source | (unstable) | 140.0-1 | |||
| firefox-esr | source | bullseye | 128.12.0esr-1~deb11u1 | DLA-4231-1 | ||
| firefox-esr | source | bookworm | 128.12.0esr-1~deb12u1 | DSA-5950-1 | ||
| firefox-esr | source | (unstable) | 128.12.0esr-1 | |||
| thunderbird | source | bullseye | 1:128.12.0esr-1~deb11u1 | DLA-4239-1 | ||
| thunderbird | source | bookworm | 1:128.12.0esr-1~deb12u1 | DSA-5959-1 | ||
| thunderbird | source | (unstable) | 1:128.12.0esr-1 |
https://www.mozilla.org/en-US/security/advisories/mfsa2025-51/#CVE-2025-6429
https://www.mozilla.org/en-US/security/advisories/mfsa2025-53/#CVE-2025-6429
https://www.mozilla.org/en-US/security/advisories/mfsa2025-54/#CVE-2025-6429