CVE-2026-2764 is a security vulnerability identified in the Just-In-Time (JIT) compilation component of the JavaScript engine used by Mozilla Firefox. The flaw arises from a miscompilation issue during JIT processing, leading to a use-after-free condition. Use-after-free vulnerabilities occur when a program continues to use memory after it has been freed, which can result in memory corruption. In this case, the vulnerability affects Firefox versions earlier than 148 and Firefox Extended Support Release (ESR) versions earlier than 115.33 and 140.8. The JIT engine is responsible for dynamically compiling JavaScript code to improve performance, but this vulnerability can be triggered by specially crafted JavaScript code that causes the engine to mismanage memory. Exploiting this flaw could allow an attacker to execute arbitrary code within the context of the browser, potentially leading to full system compromise, data theft, or denial of service. Although no exploits have been reported in the wild yet, the vulnerability is significant due to the widespread use of Firefox and the critical role of the JavaScript engine in web browsing. The lack of a CVSS score means severity must be inferred from the nature of the flaw: remote code execution vulnerabilities in popular browsers are typically high risk. The vulnerability requires no authentication but likely needs user interaction, such as visiting a malicious website or opening a malicious link. The vulnerability was published on February 24, 2026, with Mozilla as the assigner, but no official patch links are provided in the data, indicating that users should monitor Mozilla's official channels for updates.

The potential impact of CVE-2026-2764 is substantial for organizations and individual users worldwide. Successful exploitation could allow attackers to execute arbitrary code remotely, leading to unauthorized access to sensitive data, installation of malware, or complete system takeover. This threatens confidentiality by exposing private information, integrity by allowing unauthorized modifications, and availability by causing browser crashes or system instability. Organizations relying on Firefox for daily operations, especially those handling sensitive or regulated data, face increased risk of data breaches and operational disruptions. The vulnerability could be leveraged in targeted attacks or widespread campaigns, particularly through malicious websites or phishing. Since Firefox is widely used across government, education, and enterprise sectors, the scope of affected systems is broad. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as attackers may develop exploits once patches are released. Failure to promptly address this vulnerability could lead to significant reputational damage and financial losses for affected organizations.

To mitigate CVE-2026-2764, organizations and users should immediately update Mozilla Firefox to version 148 or later, or the corresponding ESR versions 115.33 or 140.8 once official patches are released. Until patches are applied, consider disabling JavaScript execution on untrusted or unknown websites using browser settings or extensions that control script execution. Employ network-level protections such as web filtering and intrusion prevention systems to block access to known malicious domains. Security teams should monitor threat intelligence feeds and Mozilla advisories for updates and exploit reports. Conduct user awareness training to avoid clicking on suspicious links or visiting untrusted websites. For high-security environments, consider using browser sandboxing or virtualization technologies to limit the impact of potential exploitation. Regularly audit and update endpoint protection solutions to detect anomalous behaviors indicative of exploitation attempts. Finally, maintain comprehensive backup and incident response plans to quickly recover from any successful attacks.