CVE-2026-6777

Name: CVE-2026-6777
Creator: NVD / NIST
Published: 2026-04-21T13:16:23.43+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 0.16%

Last modified Jun 17, 2026

CVE-2026-6777 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. Other issue in the Networking: DNS component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.. EPSS estimates a 0.16% chance of exploitation in the next 30 days.

Description

Other issue in the Networking: DNS component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.

Metrics

CVSS 3.1

5.3/10

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

EPSS Probability

0.16%

5.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 150.0
Mozilla	Thunderbird	< 150.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2022726Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-30/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-33/Vendor Advisory

Timeline

Published: Apr 21, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-6777?

Other issue in the Networking: DNS component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.

How severe is CVE-2026-6777?

CVE-2026-6777 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.16% probability of exploitation in the next 30 days.

How do I fix CVE-2026-6777?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-6777?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST