CVE-2025-27935 is a vulnerability classified under CWE-306 (Missing Authentication for Critical Function) found in the One-Time Passcode Integration Kit for PingFederate version 1.0. The vulnerability stems from the integration kit's failure to properly enforce HTTP method validation and state validation during the authentication process. Specifically, the server advances the authentication state without verifying the submitted OTP, which is a critical step in multi-factor authentication (MFA). This flaw allows an attacker to bypass the MFA mechanism entirely, gaining unauthorized access to systems protected by PingFederate's identity federation services. The vulnerability is remotely exploitable over the network without requiring user interaction or elevated privileges beyond low-level access. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no attack prerequisites (AT:N), low privileges required (PR:L), no user interaction (UI:N), and high impact on confidentiality and integrity (VC:H, VI:H), with no impact on availability. Although no public exploits are known at this time, the vulnerability poses a significant risk to organizations using this integration kit for securing authentication flows. The lack of HTTP method validation means that attackers can manipulate requests to bypass OTP verification, and the missing state validation allows the authentication process to proceed without confirming the legitimacy of the authentication state. This undermines the fundamental security guarantees of MFA, potentially exposing sensitive resources to unauthorized access. The vulnerability was reserved in April 2025 and published in December 2025, with no patches currently listed, indicating that organizations must monitor vendor advisories closely. Given the critical role of PingFederate in identity and access management, this vulnerability could have widespread implications if exploited.

The primary impact of CVE-2025-27935 is the bypass of multi-factor authentication, which significantly weakens the security posture of affected systems. For European organizations, this can lead to unauthorized access to sensitive data, internal networks, and critical applications protected by PingFederate's MFA mechanisms. The confidentiality and integrity of user credentials and session states are at risk, potentially enabling attackers to impersonate legitimate users and escalate privileges. This can result in data breaches, regulatory non-compliance (e.g., GDPR violations), and operational disruptions. Sectors such as finance, healthcare, government, and critical infrastructure, which rely heavily on strong authentication controls, are particularly vulnerable. The vulnerability's network-based exploitation vector means attackers can attempt remote attacks without physical access, increasing the threat surface. The absence of user interaction requirements facilitates automated exploitation attempts. Although availability is not directly impacted, the compromise of authentication mechanisms can indirectly lead to denial of service or further attacks. The lack of known exploits in the wild currently reduces immediate risk but does not diminish the potential severity once exploit code becomes available.

1. Monitor Ping Identity advisories closely and apply security patches or updates as soon as they are released for the OTP Integration Kit for PingFederate. 2. Implement strict HTTP method validation on all authentication endpoints to ensure only expected methods (e.g., POST) are accepted. 3. Enhance state validation logic within the authentication flow to verify the legitimacy and integrity of authentication states before advancing. 4. Employ additional layers of security such as network segmentation and anomaly detection to identify and block suspicious authentication attempts. 5. Conduct thorough security testing and code review of custom integrations involving the OTP kit to identify and remediate similar logic flaws. 6. Use compensating controls such as adaptive authentication or risk-based access policies to mitigate potential bypass scenarios. 7. Educate security teams and administrators about this vulnerability to ensure rapid detection and response to suspicious activities. 8. Consider temporary mitigation by restricting access to the vulnerable integration endpoints via firewall rules or VPN access until patches are applied.