CVE-2025-5270 | BDVDB-2026-280357 Detail

MozillaFirefox

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.

Impact#

Per CVSS v3.1: confidentiality impact high, integrity impact none, availability impact none. Attack vector: network.

Weaknesses#

CWE-319 Cleartext Transmission of Sensitive Information

References#

Exploit#

No public exploit known

History#

Version 12025-05-27Record published in the CVE List.
Version 22026-04-13Most recent update recorded in the CVE List.

Published

Published: 2025-05-27
Last modified: 2026-04-13

Vendor information

Vendor: Mozilla
Product: Firefox

All Mozilla vulnerabilities

Score

7.5 High

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 21.2.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Not classified

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
Not stated
Fixed
139

Scoring System

CVSS v4.0

Not available

CVSS v3.1

7.5 High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	None
User Interaction	None
Scope	Unchanged
Confidentiality	High
Integrity	None
Availability	None

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).