CVE-2026-8946: Incorrect boundary conditions in the Audio/Video: Web Codecs component

Published May 19, 2026
·
Updated

Incorrect boundary conditions in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Affected Software

9 affected componentsFixes available
Mozilla Firefox ESR<115.36
115.36
Mozilla Firefox<151
151
Mozilla Firefox ESR<140.11
140.11
Mozilla Thunderbird<151
151
Mozilla Thunderbird<140.11
140.11
Mozilla Firefox<115.36.0
Mozilla Firefox<151.0.0
Mozilla Firefox>=140.0<140.11.0
Mozilla Thunderbird<140.11

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 115.36
  2. Upgrade

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

    Fixed in 151
  3. Upgrade

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

    Fixed in 140.11
  4. Upgrade

    Upgrade Mozilla Firefox to a version that resolves this vulnerability.

    Fixed in 151
  5. Upgrade

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

    Fixed in 115.36
  6. Upgrade

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

    Fixed in 140.11
  7. Upgrade

    Upgrade Mozilla Thunderbird to a version that resolves this vulnerability.

    Fixed in 151
  8. Upgrade

    Upgrade Mozilla Thunderbird to a version that resolves this vulnerability.

    Fixed in 140.11

Event History

May 19, 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·12:29 PM
Data Sourced
via MITRE·12:29 PM
Description
Data Sourced
via Red Hat·02:02 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·02:16 PM
DescriptionSeverityWeaknessAffected Software
Apr 28, 58520
Event
via FIRST·07:11 AM

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-2026-8946?

CVE-2026-8946 has been categorized as a moderate severity vulnerability that affects the Audio/Video: Web Codecs component.

2

How do I fix CVE-2026-8946?

To fix CVE-2026-8946, upgrade to Firefox version 151, Firefox ESR version 115.36, or the respective updated versions of Thunderbird.

3

Which products are affected by CVE-2026-8946?

CVE-2026-8946 impacts Mozilla Firefox and Thunderbird versions below 151 and 151 respectively, as well as Firefox ESR versions below 115.36.

4

What are the new versions available to mitigate CVE-2026-8946?

The newly available versions to mitigate CVE-2026-8946 are Firefox 151, Firefox ESR 115.36, Thunderbird 151, and Thunderbird 140.11.

5

What type of vulnerability is CVE-2026-8946?

CVE-2026-8946 is characterized as an incorrect boundary condition vulnerability in the Web Codecs component.

Company

Resources

Contact

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