Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable no

Technical Impact partial

Affected Vendors & Products

Vendors Products
Mozilla
  • Firefox
  • Thunderbird

Configuration 1 [-]

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

No data.

References
Link Providers
https://bugzilla.mozilla.org/show_bug.cgi?id=2021666 cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-6763 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-6763 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-30/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-32/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-32/#CVE-2026-6763 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-33/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-34/ cve-icon cve-icon
History

Wed, 22 Apr 2026 17:45:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
Vendors & Products Mozilla thunderbird

Wed, 22 Apr 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-66
References
Metrics threat_severity

None

 threat_severity

Moderate

Wed, 22 Apr 2026 08:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-284

Wed, 22 Apr 2026 03:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-284

Wed, 22 Apr 2026 00:00:00 +0000

Type Values Removed Values Added
Description Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 150 and Firefox ESR 140.10. Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
Weaknesses CWE-693
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

ssvc

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

Tue, 21 Apr 2026 17:15:00 +0000

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

Tue, 21 Apr 2026 13:15:00 +0000

Type Values Removed Values Added
Description Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 150 and Firefox ESR 140.10.
Title Mitigation bypass in the File Handling component
References
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published: 2026-04-21T12:40:57.591Z

Updated: 2026-04-21T23:34:56.036Z

Reserved: 2026-04-21T12:40:57.216Z

Link: CVE-2026-6763

cve-icon Vulnrichment

Updated: 2026-04-21T20:12:02.113Z

cve-icon NVD

Status : Analyzed

Published: 2026-04-21T13:16:22.227

Modified: 2026-04-22T17:38:00.877

Link: CVE-2026-6763

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-04-21T12:40:57Z

Links: CVE-2026-6763 - Bugzilla