CVE-2026-74949: Privilege escalation due to use-after-free in the Graphics: Canvas2D component

Published Aug 18, 2026
·
Updated

Privilege escalation due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1.

Affected Software

6 affected componentsFixes available
Mozilla Firefox=154
Mozilla Firefox ESR 140=140.14
Mozilla Firefox ESR 153=153.1
Mozilla Firefox ESR<140.14
140.14
Mozilla Firefox<154
154
Mozilla Firefox ESR<153.1
153.1

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 140.14
  2. Upgrade

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

    Fixed in 154
  3. Upgrade

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

    Fixed in 153.1
  4. Upgrade

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

    Fixed in 154
  5. Upgrade

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

    Fixed in 140.14
  6. Upgrade

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

    Fixed in 153.1

Event History

Aug 18, 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·12:23 PM
Data Sourced
via MITRE·12:23 PM
Description

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

Which Firefox deployments need updating?

Firefox versions before 154 are affected. For ESR releases, the fixes are in Firefox ESR 140.14 and Firefox ESR 153.1; deployments on earlier builds in those ESR lines should be treated as affected.

2

What can be done if immediate patching is not possible?

The issue is a use-after-free in the Canvas2D graphics component that can lead to privilege escalation. The provided information does not specify any workaround or mitigation other than updating to a fixed release.

Contact

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