CVE-2026-118021: Sandbox escape due to use-after-free in the XPCOM component

Published Oct 27, 2026
·
Updated

Sandbox escape due to use-after-free in the XPCOM component. This vulnerability was fixed in Firefox 159.

Affected Software

1 affected componentFixes available
Mozilla Firefox<159
159

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 159
  2. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 159

Event History

Oct 27, 2026
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
CVE Published
via MITRE·02:06 PM
Data Sourced
via MITRE·02:06 PM
Description

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

Which Firefox versions include the fix?

The vulnerability was fixed in Firefox 159. The provided information does not identify which earlier versions are affected.

2

What security boundary could be impacted if this issue is exploited?

The issue is described as a sandbox escape in the XPCOM component. Successful exploitation could allow code to escape the browser sandbox.

Company

Resources

Contact

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