CVE-2025-66030 identifies an integer overflow vulnerability in the node-forge library, a widely used JavaScript implementation of Transport Layer Security (TLS). The vulnerability arises from improper handling of ASN.1 encoded Object Identifiers (OIDs) in versions prior to 1.3.2. Specifically, attackers can craft ASN.1 structures containing OIDs with arcs that exceed the 32-bit integer limit, causing a bitwise truncation during decoding. This truncation leads to the oversized arcs being interpreted as smaller, trusted OIDs. Since OIDs are often used to enforce security policies, such as certificate validation or cryptographic algorithm restrictions, this misinterpretation can allow attackers to bypass these downstream security checks. The flaw can be exploited remotely without authentication or user interaction, making it a significant risk in environments where node-forge is used to process untrusted ASN.1 data. Although no known exploits are reported in the wild, the vulnerability's medium CVSS score (6.3) reflects its potential to undermine confidentiality and integrity by circumventing security controls. The issue is resolved in node-forge version 1.3.2, which corrects the integer overflow handling during OID parsing.

For European organizations, the impact of CVE-2025-66030 can be substantial, especially for those relying on node-forge for cryptographic operations, certificate validation, or secure communications in web applications and services. The vulnerability enables attackers to bypass OID-based security decisions, potentially allowing unauthorized access, privilege escalation, or the acceptance of malicious certificates. This can compromise data confidentiality and integrity, disrupt trust models, and facilitate man-in-the-middle or impersonation attacks. Sectors such as finance, healthcare, government, and critical infrastructure that depend on robust TLS implementations are particularly at risk. The vulnerability's remote exploitability and lack of required privileges increase the attack surface. However, the absence of known exploits in the wild and the medium severity rating suggest that while impactful, the threat is currently moderate but warrants prompt remediation to prevent future exploitation.

European organizations should immediately audit their software dependencies to identify usage of node-forge versions below 1.3.2. The primary mitigation is to upgrade all instances of node-forge to version 1.3.2 or later, which contains the patch for this integer overflow vulnerability. Additionally, organizations should implement strict input validation and ASN.1 parsing sanity checks to detect malformed or oversized OID arcs before processing. Employing runtime application self-protection (RASP) or Web Application Firewalls (WAFs) with ASN.1 anomaly detection capabilities can provide an additional layer of defense. Security teams should also review cryptographic policy enforcement mechanisms to ensure they do not solely rely on OID values without additional verification. Regular vulnerability scanning and dependency management practices should be enhanced to detect outdated cryptographic libraries. Finally, monitoring for unusual certificate validation failures or anomalies in TLS handshakes can help identify exploitation attempts.