CVE-2026-6750
Published: 21 April 2026
Summary
CVE-2026-6750 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 13.8th 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-6 (Least Privilege) and SC-39 (Process Isolation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly mitigates the privilege escalation vulnerability by requiring timely remediation through patching affected Firefox and Thunderbird versions to the fixed releases.
Addresses the core CWE-269 improper privilege management by enforcing least privilege for processes in the WebRender component, preventing unauthorized elevation.
Process isolation in browser architectures confines WebRender to sandboxed processes, blocking privilege escalation from maliciously crafted graphics content.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Client-side privilege escalation vulnerability in browser rendering component directly enables exploitation for privilege escalation (T1068) and client execution (T1203).
NVD Description
Privilege escalation in the Graphics: WebRender component. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
Deeper analysisAI
CVE-2026-6750 is a privilege escalation vulnerability (CWE-269: Improper Privilege Management) in the Graphics: WebRender component of Mozilla products. It affects Firefox versions prior to 150, Firefox ESR prior to 115.35 and 140.10, Thunderbird prior to 150, and Thunderbird prior to 140.10. The vulnerability was published on 2026-04-21 and carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).
Remote attackers require no privileges but must trick users into some interaction, such as visiting a malicious site or processing crafted content. Low attack complexity enables exploitation over the network, potentially granting elevated privileges within the affected browser or application, resulting in high impacts to confidentiality, integrity, and availability.
Mozilla Security Advisories (MFSA 2026-30, 2026-31, 2026-32, and 2026-33) and Bugzilla entry 2023407 detail the fix applied in the listed versions. Security practitioners should prioritize updating affected Firefox and Thunderbird installations to mitigate this issue.
Details
- CWE(s)