CVE-2026-6777: Other issue in the Networking: DNS component

Published Apr 21, 2026
·
Updated

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

Affected Software

4 affected componentsFixes available
Mozilla Firefox<150
150
Mozilla Thunderbird<150
150
Mozilla Firefox<150.0
Mozilla Thunderbird<150.0

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 150
  2. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 150
  3. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 150

Event History

Apr 21, 2026
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
Updated
via Mozilla·12:00 AM
Affected Software
CVE Published
via MITRE·12:41 PM
Data Sourced
via MITRE·12:41 PM
Description
Data Sourced
via NVD·01:16 PM
DescriptionSeverityWeaknessAffected Software
May 21, 58279
Event
via FIRST·02:08 AM

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is the severity of CVE-2026-6777?

The severity of CVE-2026-6777 is classified as moderate.

2

How do I fix CVE-2026-6777?

To fix CVE-2026-6777, upgrade to Mozilla Firefox and Thunderbird version 150 or later.

3

What components are affected by CVE-2026-6777?

CVE-2026-6777 affects the Networking: DNS component in both Firefox and Thunderbird.

4

Is CVE-2026-6777 present in the latest Mozilla products?

No, CVE-2026-6777 has been fixed in the latest versions, which are Firefox and Thunderbird 150.

5

When was CVE-2026-6777 disclosed?

CVE-2026-6777 was disclosed in 2026 along with its remediation.

Contact

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