CVE-2026-24038 is an authentication bypass vulnerability in the Horilla open-source Human Resource Management System (HRMS), specifically affecting versions 1.4.0 through 1.4.x. The root cause is a flawed OTP (One-Time Password) validation mechanism. When an OTP expires, the server returns a None value. The OTP verification logic compares the user-supplied OTP with the server-side OTP using a simple equality check (user_otp == otp). If an attacker omits the otp field in their POST request, the user_otp variable is None, matching the server's None value for the expired OTP. This results in the OTP check passing erroneously, effectively bypassing two-factor authentication (2FA). Since 2FA is intended to add an additional security layer beyond username and password, this flaw allows attackers to authenticate without providing a valid OTP. The vulnerability is particularly critical if exploited against administrative accounts, as it could lead to unauthorized access to sensitive HR data, including personal employee information, payroll data, and the ability to manipulate employee records. Such access could facilitate further lateral movement within the organization’s network or data exfiltration. The CVSS v3.1 base score is 8.1, reflecting high severity due to network attack vector, low attack complexity, and high impact on confidentiality and integrity. No user interaction is required, but some privileges are needed (PR:L), indicating the attacker must have valid credentials or partial access to initiate the attack. The vulnerability has been addressed in Horilla version 1.5.0, which corrects the OTP validation logic to properly handle expired OTPs and prevent bypass. No public exploits have been reported yet, but the simplicity of the bypass makes it a significant risk if discovered by attackers. Organizations using affected versions should prioritize patching and review authentication logs for suspicious activity.

For European organizations, the impact of CVE-2026-24038 can be severe. HRMS platforms like Horilla store sensitive personal data, including employee identities, payroll, benefits, and performance records. Unauthorized access through 2FA bypass could lead to data breaches violating GDPR regulations, resulting in legal penalties and reputational damage. Attackers gaining administrative access could manipulate employee records, causing operational disruptions, payroll fraud, or insider threat activities. The integrity of HR data is critical for compliance and organizational trust; thus, exploitation could undermine these foundations. Additionally, compromised HRMS credentials might be leveraged for broader network access, enabling further attacks on corporate infrastructure. The vulnerability’s network-exploitable nature means attackers can attempt exploitation remotely, increasing risk for organizations with externally accessible HRMS portals. Given the high confidentiality and integrity impact, European companies must treat this vulnerability as a priority to avoid regulatory and operational consequences.

1. Immediate upgrade to Horilla version 1.5.0 or later, which contains the fix for the OTP bypass vulnerability. 2. If upgrading is not immediately possible, implement compensating controls such as disabling 2FA temporarily and enforcing strict password policies, though this reduces security and should be temporary. 3. Conduct thorough audits of authentication logs to detect anomalous login attempts, especially those missing OTP fields or showing unusual patterns. 4. Restrict network access to the HRMS application to trusted IP ranges or via VPN to reduce exposure to remote attackers. 5. Implement multi-layered authentication mechanisms beyond OTP, such as hardware tokens or biometric verification, to increase resilience. 6. Educate HR and IT staff about the vulnerability and signs of exploitation to enhance detection capabilities. 7. Regularly review and update incident response plans to include scenarios involving HRMS compromise. 8. Monitor threat intelligence feeds for any emerging exploits targeting this vulnerability to respond promptly.