vulnerability
MFSA2025-42 Firefox: Security Vulnerabilities fixed in Firefox 139 (CVE-2025-5266)
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 4 | (AV:N/AC:M/Au:N/C:P/I:N/A:N) | May 27, 2025 | May 28, 2025 | Apr 15, 2026 |
Severity
4
CVSS
(AV:N/AC:M/Au:N/C:P/I:N/A:N)
Published
May 27, 2025
Added
May 28, 2025
Modified
Apr 15, 2026
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.
Solution
mozilla-firefox-upgrade-139_0
Rapid7 Labs
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