CVE-2026-6754 is a use-after-free vulnerability affecting the JavaScript Engine component in Mozilla Firefox. Use-after-free bugs occur when a program continues to use memory after it has been freed, potentially leading to memory corruption. This vulnerability was fixed in Firefox 150 and the corresponding ESR versions 115.35 and 140.10. Mozilla has assigned a high impact rating to this vulnerability, reflecting the potential severity of exploitation. The fix is included in official releases, and no active exploitation has been reported.

The vulnerability allows for use-after-free conditions in the JavaScript Engine, which can lead to memory corruption. Such issues can be leveraged to cause crashes or potentially execute arbitrary code, posing a significant security risk. Mozilla rates the impact as high, indicating that exploitation could have serious consequences for affected users. However, there are no known exploits in the wild currently.

A fix for CVE-2026-6754 is available and has been incorporated into Firefox 150, Firefox ESR 115.35, and Firefox ESR 140.10. Users and administrators should update to these versions or later to remediate this vulnerability. Since the vendor advisory confirms the issue is fixed in these releases, no additional mitigation steps are required beyond applying the official update.