CVE-2026-2769 Mozilla CVE debrief

Who should care

Organizations and individuals using Mozilla Firefox, Firefox ESR, and Thunderbird should prioritize patching this vulnerability to prevent potential exploitation. This vulnerability can be used to execute arbitrary code, making it a critical fix for users of these applications. Security teams should review their inventory of affected systems and apply the necessary patches.

Technical summary

The CVE-2026-2769 vulnerability is caused by a use-after-free in the Storage: IndexedDB component of Mozilla Firefox, Firefox ESR, and Thunderbird. This type of vulnerability occurs when a program attempts to access memory that has already been freed or deleted, leading to potential code execution. The vulnerability has been patched in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8. Users of these applications should update to the latest versions to mitigate the risk. The CVSS vector for this vulnerability is CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

Defensive priority

This vulnerability should be prioritized for immediate patching due to its high severity and potential for code execution. Security teams should focus on patching affected systems as soon as possible to minimize the risk of exploitation.

Recommended defensive actions

• Patch Firefox to version 148 or later
• Patch Firefox ESR to version 115.33 or later
• Patch Firefox ESR to version 140.8 or later
• Patch Thunderbird to version 148 or later
• Patch Thunderbird to version 140.8 or later

Evidence notes

The CVE record and NVD detail provide comprehensive information about the vulnerability, including its CVSS score, vector, and affected products. Vendor advisories from Mozilla and Red Hat provide additional context and mitigation strategies.

Official resources