CVE-2026-2770 is a use-after-free vulnerability located in the DOM Bindings (WebIDL) component of Mozilla Firefox. Use-after-free vulnerabilities occur when a program continues to use a pointer after the memory it points to has been freed, leading to undefined behavior such as memory corruption, crashes, or arbitrary code execution. In this case, the flaw resides in the WebIDL bindings, which are responsible for connecting JavaScript code to underlying browser engine implementations. This vulnerability affects Firefox versions earlier than 148, Firefox ESR versions earlier than 115.33, and ESR versions earlier than 140.8. The absence of a CVSS score indicates that the vulnerability is newly published and has not yet been fully assessed or exploited in the wild. However, use-after-free bugs in browsers are typically severe due to their potential for remote exploitation without authentication or user interaction. Attackers could craft malicious web content that triggers the vulnerability, leading to execution of arbitrary code within the context of the browser process. This could allow attackers to steal sensitive information, install malware, or disrupt browser availability. The vulnerability is particularly critical because Firefox is widely used across many sectors, including government, enterprise, and individual users. The lack of known exploits suggests that the vulnerability was responsibly disclosed and patched promptly, but the risk remains until users update their browsers. The technical details confirm the vulnerability was reserved and published in February 2026, with Mozilla as the assigner, but no patch links are currently provided in the data, indicating that users should monitor official Mozilla channels for updates.

The impact of CVE-2026-2770 is significant due to the potential for remote code execution in a widely used web browser. Successful exploitation could compromise user confidentiality by exposing sensitive data accessible through the browser, such as cookies, saved passwords, or session tokens. Integrity could be affected if attackers manipulate web content or browser behavior, and availability could be disrupted by crashes or denial-of-service conditions. Organizations relying on Firefox for secure browsing, including government agencies, financial institutions, and enterprises, face increased risk of targeted attacks leveraging this vulnerability. The widespread deployment of Firefox ESR versions in enterprise environments increases the scope of affected systems. Additionally, the vulnerability could be used as an initial attack vector to gain foothold in networks, leading to further lateral movement or data exfiltration. Although no exploits are currently known in the wild, the nature of use-after-free vulnerabilities and their history in browser exploitation suggest a high potential for future attacks if patches are not applied promptly.

1. Immediately update Mozilla Firefox to version 148 or later, and Firefox ESR to versions 115.33 or 140.8 or later once official patches are released. 2. Until patches are available, consider deploying browser isolation or sandboxing technologies to limit the impact of potential exploitation. 3. Use security-focused browser configurations that disable or restrict JavaScript execution on untrusted sites, such as enabling Content Security Policy (CSP) or using script-blocking extensions. 4. Employ network-level protections such as web filtering to block access to known malicious sites that could host exploit code. 5. Monitor Mozilla security advisories and threat intelligence feeds for updates on exploit development and patch availability. 6. Conduct internal vulnerability scanning and endpoint detection to identify any signs of exploitation attempts related to this vulnerability. 7. Educate users on safe browsing practices and the risks of visiting untrusted websites. 8. For enterprise environments, consider deploying automated patch management systems to ensure timely updates across all endpoints.