CVE-2026-6749: Information disclosure due to uninitialized memory in the Graphics: Canvas2D component

Published Apr 21, 2026
·
Updated

Information disclosure due to uninitialized memory in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

Affected Software

9 affected componentsFixes available
Mozilla Firefox ESR<115.35
115.35
Mozilla Firefox ESR<140.10
140.10
Mozilla Firefox<150
150
Mozilla Thunderbird<150
150
Mozilla Thunderbird<140.10
140.10
Mozilla Firefox<115.35.0
Mozilla Firefox<150.0
Mozilla Firefox>=140.0<140.10.0
Mozilla Thunderbird<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 115.35
  2. Upgrade

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

    Fixed in 140.10
  3. Upgrade

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

    Fixed in 150
  4. Upgrade

    Upgrade Firefox / Firefox ESR / Thunderbird (Graphics: Canvas2D) to a version that resolves this vulnerability.

    Fixed in 150
  5. Upgrade

    Upgrade Firefox ESR / Thunderbird (Graphics: Canvas2D) to a version that resolves this vulnerability.

    Fixed in 115.35
  6. Upgrade

    Upgrade Firefox ESR / Thunderbird (Graphics: Canvas2D) 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·02:02 PM
DescriptionSeverityAffected Software
May 2, 58290
Event
via FIRST·06:03 AM

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is the severity of CVE-2026-6749?

CVE-2026-6749 is classified as an information disclosure vulnerability.

2

How do I fix CVE-2026-6749?

To fix CVE-2026-6749, update to Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, or Thunderbird 140.10.

3

What types of software are affected by CVE-2026-6749?

CVE-2026-6749 affects Mozilla Firefox, Firefox ESR, and Thunderbird versions prior to the specified patched versions.

4

What is the root cause of CVE-2026-6749?

CVE-2026-6749 is caused by information disclosure due to uninitialized memory in the Graphics: Canvas2D component.

5

Is there a workaround for CVE-2026-6749?

There is no specific workaround for CVE-2026-6749; the recommended action is to update the affected software.

Contact

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