Description
Sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
Published: 2026-06-16
Score: 9.6 Critical
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

This vulnerability allows an attacker to escape the process sandbox enforced by Mozilla applications, potentially enabling the execution of arbitrary code outside the sandbox.

Affected Systems

Mozilla Firefox versions prior to 152 and prior to 152 and ESR 140.12 are affected. Both desktop browsers and email clients share the same vulnerable sandboxing component.

Risk and Exploitability

The EPSS score indicates a very low current exploitation probability (<1%), and the flaw is not listed in the CISA KEV catalog. Based on the description, it is inferred that the attack vector is most likely local, potentially involving a malicious document or script executed within the affected application; however, the CVE description does not explicitly state this. The CVSS score of 9.6 highlights the critical severity of this vulnerability.

Generated by OpenCVE AI on June 18, 2026 at 22:33 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the vendor patch by upgrading to Firefox 152 or later, or ESR 140.12 or later.
  • Apply the vendor patch by upgrading to Thunderbird 152 or later, or ESR 140.12 or later.
  • Enable automatic updates for Firefox and Thunderbird to ensure timely receipt of future security fixes.

Generated by OpenCVE AI on June 18, 2026 at 22:33 UTC.

Tracking

Sign in to view the affected projects.

Advisories
Source ID Title
Debian DSA Debian DSA DSA-6350-1 firefox-esr security update
Debian DSA Debian DSA DSA-6351-1 thunderbird security update
History

Thu, 18 Jun 2026 19:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-264
CWE-272

Thu, 18 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-403
CWE-693
References
Metrics threat_severity

None

 cvssV3_1

{'score': 9.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

threat_severity

Important

Thu, 18 Jun 2026 04:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-264
CWE-272

Tue, 16 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
Description Sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 152 and Firefox ESR 140.12. Sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
References

Tue, 16 Jun 2026 15:15:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox

Tue, 16 Jun 2026 13:15:00 +0000

Type Values Removed Values Added
Description Sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 152 and Firefox ESR 140.12.
Title Sandbox escape in the Security: Process Sandboxing component
References

Subscriptions

Mozilla Firefox
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-06-18T16:11:00.665Z

Reserved: 2026-06-15T15:08:08.752Z

Link: CVE-2026-12296

cve-icon Vulnrichment

Updated: 2026-06-18T14:21:38.447Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-06-16T13:16:29.833

Modified: 2026-06-16T17:16:33.533

Link: CVE-2026-12296

cve-icon Redhat

Severity : Important

Publid Date: 2026-06-16T11:52:29Z

Links: CVE-2026-12296 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-06-18T22:45:16Z

Weaknesses
  • CWE-403

    Exposure of File Descriptor to Unintended Control Sphere ('File Descriptor Leak')

  • CWE-693

    Protection Mechanism Failure