CVE-2025-70043 Overview
An improper certificate validation vulnerability (CWE-295) has been discovered in the Ayms node-To Node.js library. The application disables TLS/SSL certificate validation by setting rejectUnauthorized: false in TLS socket options, which allows attackers to perform man-in-the-middle attacks and intercept encrypted communications.
Critical Impact
This vulnerability enables attackers to intercept, read, and modify sensitive data transmitted over supposedly secure TLS connections, completely undermining the security guarantees of HTTPS communications.
Affected Products
- Ayms node-To (master branch)
- Applications utilizing the node-To library for TLS/SSL connections
- Any downstream projects dependent on node-To for secure communications
Discovery Timeline
- 2026-02-23 - CVE CVE-2025-70043 published to NVD
- 2026-02-23 - Last updated in NVD database
Technical Details for CVE-2025-70043
Vulnerability Analysis
This vulnerability stems from the intentional disabling of TLS certificate verification in the node-To library. When TLS connections are established, the library explicitly sets rejectUnauthorized: false in the TLS socket configuration, which instructs Node.js to accept any certificate presented by the server, regardless of its validity, expiration status, or whether it was issued by a trusted Certificate Authority.
The impact of this vulnerability is significant because it completely negates the authentication and integrity guarantees provided by TLS. An attacker positioned between the client and server can present their own certificate, intercept all traffic, and either passively monitor communications or actively modify data in transit without detection.
Root Cause
The root cause is the explicit disabling of certificate validation in the TLS socket options. In Node.js, the rejectUnauthorized option defaults to true, which enforces proper certificate chain validation. By setting this option to false, the library bypasses all certificate verification checks, including:
- Certificate chain validation against trusted Certificate Authorities
- Certificate expiration date verification
- Hostname verification matching the certificate's Common Name or Subject Alternative Names
- Certificate revocation status checking
This configuration pattern is sometimes used during development to bypass self-signed certificate errors but should never be present in production code.
Attack Vector
The vulnerability is exploitable via network-based man-in-the-middle (MITM) attacks. An attacker must be positioned to intercept network traffic between the vulnerable application and its intended server. This can occur in various scenarios:
- On shared or compromised network infrastructure
- Through ARP spoofing on local networks
- Via DNS hijacking or poisoning
- Through compromised routers or network appliances
- On malicious Wi-Fi access points
Once positioned, the attacker can present any TLS certificate, including self-signed certificates, and the vulnerable application will accept it without warning, allowing the attacker to decrypt, inspect, and modify all traffic.
Detection Methods for CVE-2025-70043
Indicators of Compromise
- Unexpected certificate warnings or errors in client applications that were previously suppressed
- Network traffic analysis showing connections to unexpected IP addresses for known services
- Log entries indicating TLS handshakes with certificates not matching expected issuers
- Anomalous certificate fingerprints in connection logs
Detection Strategies
- Conduct static code analysis to identify instances of rejectUnauthorized: false in Node.js applications
- Review application dependencies for the vulnerable node-To library
- Monitor TLS handshake metadata for connections using self-signed or untrusted certificates
- Implement certificate pinning validation at the network level to detect mismatched certificates
Monitoring Recommendations
- Enable verbose TLS logging in production environments to capture certificate details
- Deploy network monitoring tools to analyze TLS certificate chains in real-time
- Implement alerting for applications making outbound TLS connections without proper certificate validation
- Regularly audit application dependencies for known vulnerable packages
How to Mitigate CVE-2025-70043
Immediate Actions Required
- Review all code using the node-To library and identify where it establishes TLS connections
- Remove or replace the vulnerable library with an alternative that properly validates certificates
- Audit other dependencies for similar improper certificate validation patterns
- Implement certificate pinning for critical external connections
Patch Information
No official patch has been published by the vendor at this time. Organizations should monitor the node-To GitHub repository for security updates. Additional technical details about this vulnerability are available in the security researcher's disclosure.
Workarounds
- Fork the library and modify the TLS options to set rejectUnauthorized: true or remove the option entirely to use Node.js defaults
- Replace the vulnerable library with an alternative that properly validates TLS certificates
- If the library must be used, implement a custom TLS agent that enforces certificate validation
- Deploy network-level TLS inspection to detect and block connections with invalid certificates
# Example: Verify TLS configuration in Node.js applications
# Search for improper certificate validation patterns
grep -r "rejectUnauthorized.*false" ./node_modules/
grep -r "rejectUnauthorized.*false" ./src/
# Check if node-To is installed
npm list node-To 2>/dev/null || echo "node-To not found"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
