CVE-2025-10529 — Permissive Cross-domain Security Policy with Untrusted Domains in Mozilla Firefox

CWE-942 — Permissive Cross-domain Security Policy with Untrusted Domains11 documents8 sources
Severity
6.5MEDIUMNVD
EPSS
0.1%
top 80.55%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Mozilla ThunderbirdMozilla Firefox
Timeline
PublishedSep 16
Latest updateFeb 2

Description

Same-origin policy bypass in the Layout component. This vulnerability was fixed in Firefox 143, Firefox ESR 140.3, Thunderbird 143, and Thunderbird 140.3.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:NExploitability: 3.9 | Impact: 2.5

Affected Packages3 packages

▶NVDmozilla/firefox< 140.3.0+1
▶NVDmozilla/thunderbird< 143.0
▶Debianmozilla/thunderbird< 1:140.3.0esr-1~deb11u1+3

🔴Vulnerability Details

3
GHSA
GHSA-9qv5-m6vr-vh73: This vulnerability affects Firefox < 143, Firefox ESR < 140↗2025-09-16
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CVEList
Same-origin policy bypass in the Layout component↗2025-09-16
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OSV
CVE-2025-10529: Same-origin policy bypass in the Layout component↗2025-09-16
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📋Vendor Advisories

7
Ubuntu
Thunderbird vulnerabilities↗2026-02-02
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Red Hat
firefox: thunderbird: Same-origin policy bypass in the Layout component↗2025-09-16
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Debian
CVE-2025-10529: firefox - Same-origin policy bypass in the Layout component. This vulnerability affects Fi...↗2025
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Mozilla
Mozilla Foundation Security Advisory 2025-78: CVE-2025-10529↗
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Mozilla
Mozilla Foundation Security Advisory 2025-77: CVE-2025-10529↗
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CVE-2025-10529 — Mozilla Firefox vulnerability | cvebase