CVE-2026-2800 identifies a spoofing vulnerability within the WebAuthn component of Mozilla Firefox for Android devices running versions earlier than 148. WebAuthn is a web standard designed to provide strong, phishing-resistant authentication by leveraging public key cryptography and hardware authenticators. The vulnerability allows an attacker to spoof authentication prompts or responses, potentially tricking users or systems into accepting fraudulent authentication events. This undermines the integrity of the authentication process, possibly enabling unauthorized access or session hijacking. The flaw is specific to Firefox on Android, affecting all versions prior to 148, though exact affected versions are unspecified. No CVSS score has been assigned yet, and there are no known exploits in the wild. The vulnerability was reserved and published in February 2026, indicating recent discovery. The absence of patch links suggests that fixes may be forthcoming or integrated into Firefox 148. Given the critical role of WebAuthn in modern secure authentication, this vulnerability represents a significant risk to confidentiality and integrity of user sessions on affected devices.

The primary impact of CVE-2026-2800 is on the integrity and confidentiality of user authentication processes. Successful exploitation could allow attackers to impersonate legitimate authentication prompts, potentially gaining unauthorized access to user accounts or sensitive systems protected by WebAuthn. This could lead to account takeover, data breaches, and unauthorized transactions. Since WebAuthn is increasingly adopted for high-security environments, including financial services, government portals, and enterprise systems, the vulnerability could have widespread implications. The lack of known exploits reduces immediate risk but does not diminish the potential severity. Organizations relying on Firefox for Android for secure authentication may face increased risk of phishing-like attacks that bypass traditional protections. The availability impact is minimal as the vulnerability does not cause denial of service. However, the breach of authentication integrity can have cascading effects on trust and system security.

To mitigate CVE-2026-2800, organizations and users should promptly update Mozilla Firefox on Android devices to version 148 or later once the update is available. Until patches are applied, users should exercise heightened caution when interacting with authentication prompts and verify the legitimacy of WebAuthn requests. Organizations should monitor Mozilla security advisories for patch releases and consider deploying mobile device management (MDM) solutions to enforce timely updates. Additionally, implementing multi-factor authentication methods that do not solely rely on WebAuthn or combining WebAuthn with behavioral analytics can reduce risk. Security teams should educate users about phishing and spoofing risks related to authentication prompts. Network-level protections such as DNS filtering and endpoint security solutions can help detect and block malicious sites attempting to exploit this vulnerability. Finally, reviewing and tightening authentication policies and logs can aid in early detection of suspicious activities.