CVE-2026-6769
Published: 21 April 2026
Summary
CVE-2026-6769 is a high-severity Improper Privilege Management (CWE-269) vulnerability in Mozilla Firefox. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 13.2th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and AC-6 (Least Privilege).
Deeper analysis
CVE-2026-6769 is a privilege escalation vulnerability in the Debugger component affecting Mozilla Firefox versions prior to 150, Firefox ESR prior to 140.10, Thunderbird prior to 150, and Thunderbird prior to 140.10. Assigned CWE-269 (Improper Privilege Management), it received a CVSS v3.1 base score of 8.8 (High), reflecting network accessibility (AV:N), low attack complexity (AC:L), no required privileges (PR:N), user interaction (UI:R), unchanged scope (S:U), and high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H). The issue was publicly disclosed on 2026-04-21.
An attacker can exploit this vulnerability remotely without authentication by tricking a user into performing an action, such as interacting with a malicious webpage or debugger feature. Successful exploitation enables privilege escalation, potentially allowing the attacker to gain high-level access within the affected application, resulting in unauthorized data access, modification, or denial of service.
Mozilla's security advisories (MFSA 2026-30, 32, 33, 34) and the associated Bugzilla entry (bug 2023753) confirm the vulnerability was addressed in the specified fixed releases: Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. Security practitioners should prioritize updating affected products to these versions or later to mitigate the risk.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-24110
Vulnerability details
Privilege escalation in the Debugger component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
CVE explicitly describes a privilege escalation vulnerability (CWE-269) in the Debugger component that can be remotely triggered via malicious webpage interaction, directly mapping to T1068 Exploitation for Privilege Escalation.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates CVE-2026-6769 by requiring timely remediation of the privilege escalation flaw through patching to fixed versions like Firefox 150.
Enforces least privilege to counter the improper privilege management (CWE-269) in the Firefox Debugger component, limiting escalation impact.
Mandates enforcement of access control policies to prevent unauthorized privilege escalation via the Debugger vulnerability exploited through malicious webpages.
Hardening callouts derived
Configuration rules from DISA STIG baselines that reduce the attack surface for weaknesses of the type cited by this CVE. Derived transitively via CVE→CWE→STIG over `controls_xwalks` (authoritative rows only).
Windows 10 (1 rule)
- V-220712 Only accounts responsible for the administration of a system must have Administrator rights on the system. via CWE-269
Windows 11 (1 rule)
- V-253269 Only accounts responsible for the administration of a system must have Administrator rights on the system. via CWE-269
Windows Server 2016 (1 rule)
- V-225007 Only administrators responsible for the member server or standalone or nondomain-joined system must have Administrator rights on the system. via CWE-269
Windows Server 2019 (1 rule)
- V-205746 Windows Server 2019 must only allow Administrators responsible for the member server or standalone or nondomain-joined system to have Administrator rights on the system. via CWE-269
Windows Server 2022 (1 rule)
- V-254428 Windows Server 2022 must only allow administrators responsible for the member server or standalone or nondomain-joined system to have Administrator rights on the system. via CWE-269