Vulnerability in Mozilla Firefox
CVE-2025-5270
In certain cases, SNI could have been sent unencrypted even when encrypted DNS was enabled. This vulnerability was fixed in Firefox 139 and Thunderbird 139.
EPSS: 0.003 (16.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Mozilla Firefox — versions 139
- Mozilla Thunderbird — versions 139
Weakness classification (CWE)
References
- security@mozilla.org (Permissions Required)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org
Frequently asked questions
- What is CVE-2025-5270?
- CVE-2025-5270 is a high-severity vulnerability in Mozilla Firefox, classified under Cleartext Transmission of Sensitive Information. CVSS score: 7.5/10. Published 2025-05-27.
- How severe is CVE-2025-5270?
- High severity. CVSS v3 base score is 7.5 out of 10.