CVE-2025-66030 is an integer overflow vulnerability classified under CWE-190 found in the node-forge library, a native JavaScript implementation of Transport Layer Security (TLS). The vulnerability exists in node-forge versions 1.3.1 and earlier, where ASN.1 structures containing Object Identifiers (OIDs) with oversized arcs can be crafted by remote attackers. Due to 32-bit bitwise truncation during decoding, these oversized arcs are interpreted as smaller, trusted OIDs, effectively bypassing security checks that rely on OID validation. This can undermine the integrity of cryptographic operations, such as certificate validation or policy enforcement, potentially allowing attackers to impersonate trusted entities or bypass security controls. Exploitation requires no authentication or user interaction and can be performed remotely by sending malicious ASN.1 data to affected systems. The vulnerability was publicly disclosed on November 26, 2025, with a CVSS v4.0 base score of 6.3, indicating medium severity. The issue has been addressed in node-forge version 1.3.2, which corrects the integer overflow and ensures proper OID arc validation. No known exploits have been reported in the wild to date.

For European organizations, the impact of CVE-2025-66030 can be significant, especially for those relying on node-forge for TLS implementations, cryptographic operations, or certificate validation in web applications, APIs, or internal services. The vulnerability could allow attackers to bypass OID-based security policies, potentially leading to unauthorized access, man-in-the-middle attacks, or the acceptance of malicious certificates. This undermines confidentiality and integrity of communications and data. Organizations in sectors such as finance, healthcare, government, and critical infrastructure that depend on strong cryptographic assurances are particularly at risk. The medium severity score reflects a moderate likelihood of exploitation combined with impactful consequences if exploited. Since no authentication or user interaction is required, the attack surface is broad, increasing the risk to exposed services. However, the absence of known exploits in the wild suggests that immediate widespread attacks are not yet observed, though proactive mitigation is essential.

1. Immediately upgrade all instances of node-forge to version 1.3.2 or later to apply the official patch addressing the integer overflow. 2. Audit all applications and services using node-forge to identify and remediate any usage of vulnerable versions. 3. Implement strict input validation and ASN.1 parsing controls where possible to detect and reject malformed or oversized OID arcs. 4. Employ network-level protections such as Web Application Firewalls (WAFs) with custom rules to detect anomalous ASN.1 structures in inbound traffic. 5. Monitor logs and network traffic for unusual TLS handshake anomalies or certificate validation errors that may indicate exploitation attempts. 6. Educate developers and security teams about the risks of integer overflow vulnerabilities in cryptographic libraries and encourage secure coding practices. 7. Consider additional cryptographic validation layers or alternative libraries if node-forge usage is extensive and critical. 8. Maintain an incident response plan to quickly address any exploitation attempts once detected.