Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable no

Technical Impact total

Affected Vendors & Products

Vendors Products
Mozilla
  • Firefox
  • Firefox Esr

Configuration 1 [-]

OR cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*

No data.

References
Link Providers
https://bugzilla.mozilla.org/show_bug.cgi?id=2016368 cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-4687 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-4687 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-20/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-21/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-22/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-22/#CVE-2026-4687 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-23/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-24/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-24/#CVE-2026-4687 cve-icon
History

Thu, 26 Mar 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-501
References
Metrics threat_severity

None

 threat_severity

Important

Wed, 25 Mar 2026 16:15:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}

 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'}

Wed, 25 Mar 2026 14:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-120
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'}

 ssvc

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

cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}

Wed, 25 Mar 2026 12:00:00 +0000

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

Tue, 24 Mar 2026 20:30:00 +0000

Type Values Removed Values Added
Description Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, and Firefox ESR < 140.9. Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
References

Tue, 24 Mar 2026 19:30:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Weaknesses CWE-754
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
Vendors & Products Mozilla
Mozilla firefox
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'}

Tue, 24 Mar 2026 12:45:00 +0000

Type Values Removed Values Added
Description Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, and Firefox ESR < 140.9.
Title Sandbox escape due to incorrect boundary conditions in the Telemetry component
References
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-03-25T14:06:49.307Z

Reserved: 2026-03-23T23:21:35.819Z

Link: CVE-2026-4687

cve-icon Vulnrichment

Updated: 2026-03-25T14:02:05.516Z

cve-icon NVD

Status : Modified

Published: 2026-03-24T13:16:04.537

Modified: 2026-03-25T15:16:51.950

Link: CVE-2026-4687

cve-icon Redhat

Severity : Important

Publid Date: 2026-03-24T12:30:22Z

Links: CVE-2026-4687 - Bugzilla