CVE-2026-6751: Uninitialized memory in the Audio/Video: Web Codecs component

Published Apr 21, 2026
·
Updated

Uninitialized memory in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

Affected Software

7 affected componentsFixes available
Mozilla Firefox ESR<140.10
140.10
Mozilla Firefox<150
150
Mozilla Thunderbird<150
150
Mozilla Thunderbird<140.10
140.10
Mozilla Firefox<140.10.0
Mozilla Firefox<150.0
Mozilla Thunderbird>=140.0<140.10.0

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 140.10
  2. Upgrade

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

    Fixed in 150
  3. Upgrade

    Upgrade Mozilla Firefox to a version that resolves this vulnerability.

    Fixed in 150
  4. Upgrade

    Upgrade Mozilla Firefox ESR to a version that resolves this vulnerability.

    Fixed in 140.10
  5. Upgrade

    Upgrade Mozilla Thunderbird to a version that resolves this vulnerability.

    Fixed in 150
  6. Upgrade

    Upgrade Mozilla Thunderbird ESR to a version that resolves this vulnerability.

    Fixed in 140.10

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·12:40 PM
Data Sourced
via MITRE·12:40 PM
Description
Data Sourced
via NVD·01:16 PM
DescriptionSeverityWeaknessAffected Software
Data Sourced
via Red Hat·02:03 PM
DescriptionSeverityAffected Software
Jan 23, 58467
Event
via NVD·04:50 PM

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

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Frequently Asked Questions

1

What is the severity of CVE-2026-6751?

CVE-2026-6751 is categorized as a moderate severity vulnerability affecting the Audio/Video: Web Codecs component.

2

How do I fix CVE-2026-6751?

To fix CVE-2026-6751, update to Firefox version 150, Firefox ESR version 140.10, Thunderbird version 150, or Thunderbird version 140.10.

3

What systems are affected by CVE-2026-6751?

CVE-2026-6751 affects Mozilla Firefox versions up to 150, Firefox ESR versions up to 140.10, and corresponding versions of Thunderbird.

4

What type of vulnerability is CVE-2026-6751?

CVE-2026-6751 is an uninitialized memory vulnerability in the Audio/Video: Web Codecs component.

5

Is there a workaround for CVE-2026-6751?

There is no specific workaround for CVE-2026-6751; the recommended action is to update the affected software.

Company

Resources

Contact

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