Vulnerability · Published Jun 24, 2025 · Assigned by mozilla
CVE-2025-6425The WebCompat WebExtension shipped with Firefox exposed a persistent UUID
Medium 4.3
In plain English
A medium-severity information exposure in Firefox from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
An attacker who enumerated resources from the WebCompat extension could have obtained a persistent UUID that identified the browser, and persisted between containers and normal/private browsing mode, but not profiles. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | firefox | 128.12.0-1.el10_0 | ALSA-2025:10073 |
| AlmaLinux:8 | firefox | 128.12.0-1.el8_10.alma.1 | ALSA-2025:10074 |
| AlmaLinux:9 | firefox | 128.12.0-1.el9_6.alma.1 | ALSA-2025:10072 |
| AlmaLinux:9 | firefox-x11 | 128.12.0-1.el9_6.alma.1 | ALSA-2025:10072 |
| AlmaLinux:8 | thunderbird | 128.12.0-1.el8_10.alma.1 | ALSA-2025:10246 |
| Debian:12 | firefox-esr | 128.12.0esr-1~deb12u1 | DEBIAN-CVE-2025-6425 |
| Debian:12 | firefox-esr | 128.12.0esr-1~deb12u1 | DSA-5950-1 |
| Debian:13 | firefox-esr | 128.12.0esr-1 | DEBIAN-CVE-2025-6425 |
| Debian:14 | firefox-esr | 128.12.0esr-1 | DEBIAN-CVE-2025-6425 |
| Debian:12 | thunderbird | 1:128.12.0esr-1~deb12u1 | DSA-5959-1 |
| Debian:12 | thunderbird | 1:128.12.0esr-1~deb12u1 | DEBIAN-CVE-2025-6425 |
| Debian:13 | thunderbird | 1:128.12.0esr-1 | DEBIAN-CVE-2025-6425 |
| Debian:14 | thunderbird | 1:128.12.0esr-1 | DEBIAN-CVE-2025-6425 |
| Rocky Linux:10 | firefox | 0:128.12.0-1.el10_0 | RLSA-2025:10073 |
| Rocky Linux:8 | firefox | 0:128.12.0-1.el8_10 | RLSA-2025:10074 |
| Rocky Linux:9 | firefox | 0:128.12.0-1.el9_6 | RLSA-2025:10072 |
| Rocky Linux:10 | thunderbird | 0:128.12.0-1.el10_0 | RLSA-2025:10195 |
| Rocky Linux:8 | thunderbird | 0:128.12.0-1.el8_10 | RLSA-2025:10246 |
| Rocky Linux:9 | thunderbird | 0:128.12.0-1.el9_6 | RLSA-2025:10196 |
| Ubuntu:22.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2025-6425 |
| Ubuntu:24.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2025-6425 |
| Ubuntu:24.04:LTS | mozjs115 | no fix listed | UBUNTU-CVE-2025-6425 |
| Ubuntu:22.04:LTS | mozjs78 | no fix listed | UBUNTU-CVE-2025-6425 |
| Ubuntu:22.04:LTS | mozjs91 | no fix listed | UBUNTU-CVE-2025-6425 |
| Ubuntu:22.04:LTS | thunderbird | 1:128.12.0+build1-0ubuntu0.22.04.1 | USN-7663-1 |
| Ubuntu:22.04:LTS | thunderbird | 1:128.12.0+build1-0ubuntu0.22.04.1 | UBUNTU-CVE-2025-6425 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | see references |
| Mozilla | Thunderbird | see references |
Weakness: CWE-200 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1717672
- https://www.mozilla.org/security/advisories/mfsa2025-51/
- https://www.mozilla.org/security/advisories/mfsa2025-52/
- https://www.mozilla.org/security/advisories/mfsa2025-53/
- https://www.mozilla.org/security/advisories/mfsa2025-54/
- https://www.mozilla.org/security/advisories/mfsa2025-55/
- https://lists.debian.org/debian-lts-announce/2025/07/msg00002.html
- https://lists.debian.org/debian-lts-announce/2025/06/msg00029.html