CVE-2026-2803 is a vulnerability identified in the Settings UI component of Mozilla Firefox, affecting all versions prior to 148. The flaw enables information disclosure by bypassing existing mitigation mechanisms designed to protect sensitive data within the browser's settings interface. This could allow an attacker to access configuration details or other sensitive information that should be protected, potentially leading to further exploitation or privacy breaches. The vulnerability was reserved on February 19, 2026, and published on February 24, 2026, but no CVSS score or official patch has been released as of now. The absence of known exploits in the wild suggests it is either newly discovered or not yet weaponized. The technical specifics of the bypass are not detailed, but the impact centers on confidentiality compromise through UI component weaknesses. Firefox's widespread use across personal, enterprise, and governmental environments increases the potential attack surface. Given the lack of a patch, users remain exposed until Mozilla issues an update. The vulnerability does not appear to require authentication, increasing its risk profile, though user interaction requirements are unclear. This flaw highlights the importance of securing UI components that handle sensitive data and the need for timely updates to mitigate emerging threats.

The primary impact of CVE-2026-2803 is the unauthorized disclosure of sensitive information from the Firefox Settings UI, which can compromise user privacy and confidentiality. For organizations, this could lead to leakage of configuration details that might be leveraged for further attacks, such as targeted phishing, credential theft, or exploitation of other vulnerabilities. The vulnerability could undermine trust in Firefox as a secure browsing platform, especially in environments requiring strict data protection compliance. Since Firefox is widely used globally, the scope of affected systems is extensive, including desktops and potentially mobile platforms running vulnerable versions. Although no direct code execution or integrity compromise is indicated, the information disclosure alone can facilitate more sophisticated attacks. The lack of authentication requirement lowers the barrier for exploitation, potentially allowing remote attackers to exploit the flaw if they can induce user interaction or access the affected UI. The absence of a patch prolongs exposure, increasing the window of opportunity for attackers. Overall, the impact is significant for confidentiality and privacy but does not directly affect system availability or integrity.

Until an official patch is released by Mozilla, organizations and users should take specific steps to mitigate the risk from CVE-2026-2803. First, restrict access to Firefox settings through group policies or browser management tools to limit exposure of the vulnerable UI components. Disable or limit the use of features that expose sensitive settings if possible. Monitor network and endpoint logs for unusual activity that might indicate attempts to exploit this vulnerability. Educate users about the risk and advise caution when interacting with unexpected prompts or UI elements within Firefox. Employ browser isolation or sandboxing technologies to contain potential exploitation attempts. Plan and prioritize upgrading to Firefox version 148 or later immediately upon release to remediate the vulnerability. For enterprise environments, coordinate with IT and security teams to deploy updates rapidly and verify patch application. Additionally, consider using endpoint detection and response (EDR) solutions to detect anomalous behavior related to browser exploitation. Regularly review Mozilla security advisories for updates on patches or further technical details.