CVE-2025-5270

HIGH
Published May 27, 2025 Modified Apr 13, 2026 CWE-319

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.

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CVSS v3.1 Score

7.5
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Weakness Type (CWE)

CWE-319 CWE-319

Affected Products

Vendor Product
mozilla firefox

References

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.5 (HIGH).
How severe is CVE-2025-5270? +
CVE-2025-5270 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.
What products are affected by CVE-2025-5270? +
CVE-2025-5270 affects products from mozilla, specifically: firefox. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2025-5270? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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