XSS in Mozilla Firefox
CVE-2025-8029
Thunderbird executed `javascript:` URLs when used in `object` and `embed` tags. This vulnerability was fixed in Firefox 141, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.003 (23.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 24th percentile — 23.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000
Affected products
- Mozilla Firefox — versions 128.13, 140.1, 141
- Mozilla Thunderbird — versions 128.13, 140.1, 141
Weakness classification (CWE)
Public proof-of-concept exploits
References
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required)
- www.mozilla.org/security/advisories/mfsa2025-56/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-58/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-59/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-61/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-62/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-63/ (Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2025-8029?
- CVE-2025-8029 is a high-severity vulnerability in Mozilla Firefox, classified under Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS). CVSS score: 8.1/10. Published 2025-07-22.
- How severe is CVE-2025-8029?
- High severity. CVSS v3 base score is 8.1 out of 10.
- Is CVE-2025-8029 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.