CVE-2025-8029 — Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) in Mozilla Firefox

CWE-80 — Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)13 documents8 sources
Severity
8.1HIGHNVD
EPSS
0.1%
top 80.47%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Mozilla ThunderbirdMozilla Firefox
Timeline
PublishedJul 22
Latest updateFeb 2

Description

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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:NExploitability: 2.8 | Impact: 5.2

Affected Packages3 packages

▶NVDmozilla/thunderbird140.0 — 140.1.0+2
▶Debianmozilla/thunderbird< 1:128.13.0esr-1~deb11u1+3
▶NVDmozilla/firefox140.0 — 140.1.0+2

🔴Vulnerability Details

3
CVEList
javascript: URLs executed on object and embed tags↗2025-07-22
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OSV
CVE-2025-8029: Thunderbird executed `javascript:` URLs when used in `object` and `embed` tags↗2025-07-22
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GHSA
GHSA-657p-g22x-9v25: Thunderbird executed `javascript:` URLs when used in `object` and `embed` tags↗2025-07-22
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📋Vendor Advisories

9
Ubuntu
Thunderbird vulnerabilities↗2026-02-02
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Red Hat
firefox: thunderbird: javascript: URLs executed on object and embed tags↗2025-07-22
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Debian
CVE-2025-8029: firefox - Thunderbird executed `javascript:` URLs when used in `object` and `embed` tags. ...↗2025
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Mozilla
Mozilla Foundation Security Advisory 2025-63: CVE-2025-8029↗
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Mozilla
Mozilla Foundation Security Advisory 2025-56: CVE-2025-8029↗
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CVE-2025-8029 — Mozilla Firefox vulnerability | cvebase