Description
Script elements loading cross-origin resources generated load and error events which leaked information enabling XS-Leaks attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.
Affected products
mozilla: firefox
References7
- www.mozilla.org/security/advisories/mfsa2025-42/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2025-44/ Vendor Advisory
- bugzilla.mozilla.org/show_bug.cgi?id=1965628 Permissions Required
- www.mozilla.org/security/advisories/mfsa2025-45/
- www.mozilla.org/security/advisories/mfsa2025-46/
- lists.debian.org/debian-lts-announce/2025/05/msg00043.html
- lists.debian.org/debian-lts-announce/2025/05/msg00046.html
Metrics
- CVSS 3.1
-
4.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N - EPSS — exploit probability
- 0% percentile: 28 · as of 7 November 2026
- CWE
- CWE-200
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