CVE-2026-2775 is a security vulnerability identified in the DOM: HTML Parser component of Mozilla Firefox. The issue is characterized as a mitigation bypass, meaning that it allows attackers to circumvent existing security mechanisms designed to protect the browser from malicious content during HTML parsing. This vulnerability affects Firefox versions earlier than 148, as well as Firefox ESR (Extended Support Release) versions earlier than 115.33 and 140.8. The DOM HTML Parser is a critical component responsible for interpreting and processing HTML content received from the web. A bypass in this component can enable attackers to craft malicious HTML that evades built-in security mitigations, potentially leading to further exploitation such as arbitrary code execution, cross-site scripting (XSS), or other injection attacks. Although no known exploits have been reported in the wild at the time of publication, the nature of the vulnerability suggests it could be leveraged in targeted attacks or drive-by compromise scenarios. The lack of a CVSS score indicates that the vulnerability is newly disclosed and pending detailed scoring, but the technical details imply a significant risk due to the central role of the HTML parser in browser security. The vulnerability affects a broad user base given Firefox's global usage, including organizations relying on ESR versions for stability and long-term support. The absence of patch links in the provided data suggests that users should monitor Mozilla's official channels for updates and advisories. Overall, this vulnerability represents a critical weakness in browser security that could undermine user trust and system integrity if exploited.

The potential impact of CVE-2026-2775 is substantial for organizations worldwide that use Mozilla Firefox as their primary web browser. Since the vulnerability allows bypassing security mitigations in the HTML parser, attackers could exploit it to execute malicious scripts, perform cross-site scripting attacks, or escalate privileges within the browser context. This could lead to unauthorized access to sensitive information, session hijacking, or delivery of malware payloads. The compromise of browser security can also serve as a foothold for further network intrusion or lateral movement within an organization. Given Firefox's widespread use in both consumer and enterprise environments, the vulnerability poses risks to data confidentiality, integrity, and availability. Enterprises using Firefox ESR versions for stability and compliance are particularly vulnerable if they have not updated to the fixed versions. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, as attackers may develop exploits rapidly following disclosure. Additionally, the vulnerability could be leveraged in targeted attacks against high-value targets or in mass exploitation campaigns if weaponized. The impact extends to user trust and compliance with security policies, potentially affecting regulatory adherence if breaches occur due to unpatched browsers.

To mitigate CVE-2026-2775 effectively, organizations should prioritize updating Mozilla Firefox to version 148 or later, and Firefox ESR to versions 115.33 or 140.8 and above as soon as official patches are released. Until patches are available, organizations should consider implementing the following additional measures: 1) Enforce strict web content filtering and block access to untrusted or suspicious websites to reduce exposure to malicious HTML content. 2) Utilize browser security extensions or sandboxing technologies that add layers of defense against exploitation of browser vulnerabilities. 3) Monitor network traffic and endpoint logs for unusual activity indicative of exploitation attempts, such as unexpected script execution or anomalous web requests. 4) Educate users on the risks of visiting untrusted websites and opening unknown links to reduce the likelihood of triggering the vulnerability. 5) Employ endpoint detection and response (EDR) tools capable of identifying exploitation behaviors related to browser vulnerabilities. 6) Maintain an inventory of browser versions in use across the organization to ensure timely patch management. These steps, combined with prompt patching, will reduce the risk posed by this vulnerability.