CVE-2025-5270

SNI was sometimes unencrypted

State: Published
Severity: 7.5 High
Published: May 27, 2025
Updated: Apr 13, 2026
Reserved: May 27, 2025

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N	CISA-ADP

Weaknesses

CWE-319 Cleartext Transmission of Sensitive Information

Affected Products

Product	Versions
FirefoxMozilla	139 and laterNot affected
ThunderbirdMozilla	139 and laterNot affected

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1910298
https://www.mozilla.org/security/advisories/mfsa2025-42/
https://www.mozilla.org/security/advisories/mfsa2025-45/

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