CVE-2025-6545 is a critical vulnerability classified under CWE-20 (Improper Input Validation) affecting the pbkdf2 library versions from 3.0.10 through 3.1.2. The vulnerability resides in the program file lib/to-buffer.js and involves improper validation of inputs during the cryptographic process, specifically in the PBKDF2 (Password-Based Key Derivation Function 2) implementation. PBKDF2 is widely used for securely deriving cryptographic keys from passwords by applying a pseudorandom function, typically HMAC, iteratively to the input password along with a salt. The improper input validation flaw allows an attacker to perform signature spoofing, meaning that the attacker can craft inputs that bypass the intended cryptographic verification mechanisms, potentially causing the system to accept forged signatures or keys. This undermines the integrity and authenticity guarantees that PBKDF2 is supposed to provide. The vulnerability has a CVSS 4.0 base score of 9.1 (critical), indicating a high impact with network attack vector, low attack complexity, no privileges required, and no user interaction needed. The vulnerability impacts confidentiality (low), integrity (high), and availability (none). The scope is high, meaning the vulnerability affects components beyond the vulnerable library itself, potentially impacting dependent applications. No known exploits are currently reported in the wild, but the severity and ease of exploitation suggest that exploitation could be feasible once a proof of concept is developed. The vulnerability affects a widely used cryptographic library, which is often embedded in various applications and services for secure password handling and authentication processes. This makes the vulnerability particularly dangerous as it can compromise authentication mechanisms and lead to unauthorized access or privilege escalation in affected systems.

For European organizations, the impact of CVE-2025-6545 can be significant, especially for those relying on the affected pbkdf2 versions in their authentication or cryptographic workflows. Compromise of PBKDF2 integrity can lead to signature spoofing, allowing attackers to bypass authentication controls, impersonate users, or escalate privileges. This can result in unauthorized access to sensitive data, disruption of services, and potential regulatory non-compliance under GDPR due to compromised data integrity and confidentiality. Sectors such as finance, healthcare, government, and critical infrastructure, which often use cryptographic libraries for secure authentication, are at heightened risk. The vulnerability’s network attack vector and lack of required privileges mean that attackers can exploit it remotely without prior access, increasing the threat surface. Additionally, the high scope impact suggests that downstream applications and services that embed the vulnerable pbkdf2 library are also at risk, potentially amplifying the damage. The absence of known exploits currently provides a window for mitigation, but organizations must act swiftly to prevent exploitation. Failure to address this vulnerability could lead to data breaches, loss of customer trust, financial penalties, and operational disruptions.

1. Immediate upgrade: Organizations should promptly upgrade pbkdf2 to a patched version beyond 3.1.2 once available. Since no patch links are currently provided, monitoring official repositories and vendor advisories for updates is critical. 2. Dependency audit: Conduct a thorough audit of all software dependencies and applications to identify usage of the affected pbkdf2 versions. This includes direct and transitive dependencies in software supply chains. 3. Temporary mitigations: If immediate upgrade is not feasible, consider implementing compensating controls such as additional input validation layers, restricting network access to vulnerable services, and enhanced monitoring for anomalous authentication attempts. 4. Cryptographic verification: Validate the integrity of cryptographic operations by implementing additional signature verification mechanisms or using alternative, trusted cryptographic libraries where possible. 5. Incident response readiness: Prepare for potential exploitation by updating incident response plans to detect and respond to signature spoofing or unauthorized access attempts. 6. Vendor engagement: Engage with software vendors and maintainers to prioritize patch development and deployment. 7. Security testing: Perform penetration testing and code reviews focusing on cryptographic modules to identify similar input validation issues. 8. Awareness and training: Educate development and security teams about the risks of improper input validation in cryptographic functions and best practices for secure coding.