CVE-2025-47949 is a critical vulnerability identified in the samlify library, a Node.js implementation used for SAML (Security Assertion Markup Language) single sign-on (SSO) functionality. The vulnerability is classified under CWE-347, which pertains to improper verification of cryptographic signatures. Specifically, the flaw is a Signature Wrapping attack present in samlify versions prior to 2.10.0. In this attack, an adversary who has access to a legitimately signed XML document from the identity provider can manipulate the SAML Response by wrapping or injecting malicious assertions without invalidating the signature verification process. This manipulation allows the attacker to forge a SAML Response and authenticate as any user without possessing their credentials or requiring any privileges. The vulnerability is severe because it bypasses the fundamental trust model of SAML-based authentication, potentially granting unauthorized access to protected resources. The CVSS 4.0 score of 9.9 reflects the vulnerability's criticality, highlighting that it is remotely exploitable over the network without authentication or user interaction, and it impacts confidentiality, integrity, and availability with high scope and impact. The issue was addressed in samlify version 2.10.0, which implements proper cryptographic signature verification to prevent such wrapping attacks. No known exploits have been reported in the wild yet, but the high severity and ease of exploitation make it a significant threat to any system relying on vulnerable samlify versions for SAML SSO.

For European organizations, this vulnerability poses a substantial risk, especially for enterprises, government agencies, and service providers that utilize samlify for SAML-based authentication. Exploitation could lead to unauthorized access to sensitive systems and data, undermining user identity integrity and potentially enabling lateral movement within networks. The breach of authentication mechanisms can result in data breaches, regulatory non-compliance (e.g., GDPR violations), and reputational damage. Since SAML SSO is widely adopted in Europe for federated identity management across cloud services and internal applications, the impact could be widespread. Critical infrastructure sectors, financial institutions, and public sector entities are particularly at risk due to their reliance on strong authentication controls. Additionally, the ability to impersonate any user without credentials could facilitate espionage, fraud, or sabotage. The vulnerability's network-exploitable nature means attackers can launch attacks remotely, increasing the threat surface for European organizations with internet-facing SAML services.

European organizations should immediately audit their use of the samlify library and identify any deployments running versions prior to 2.10.0. The primary mitigation is to upgrade samlify to version 2.10.0 or later, where the signature verification flaw has been corrected. Organizations should also implement strict XML signature validation policies and consider additional layers of defense such as Web Application Firewalls (WAFs) with rules to detect anomalous SAML responses. Conducting thorough penetration testing focused on SAML authentication flows can help identify residual weaknesses. Monitoring authentication logs for unusual login patterns or anomalies in SAML assertions is recommended. Where possible, organizations should enforce multi-factor authentication (MFA) to reduce the impact of compromised SAML tokens. Finally, security teams should stay alert for any emerging exploits targeting this vulnerability and apply patches promptly.