Skip to content

node-forge ASN.1 Validation Bypass Vulnerability

node-forge

CVE-2025-12816
node-forge ASN.1 Validator Desynchronization
Cryptographic Verification Bypass

Overview

A vulnerability in the ASN.1 schema validator of the widely used JavaScript crypto library node-forge allows specially crafted ASN.1 structures to be treated as valid. Applications that rely on node-forge for certificate, PKCS#12, or signature verification may incorrectly accept attacker-crafted data, bypassing MACs, signature checks, or certificate validation.

Technical Specifications

Attribute Details
CVE ID CVE-2025-12816
Library node-forge
Component / Func ASN.1 validator — asn1.validate(...)
Vulnerability Type ASN.1 validator desynchronization → validation bypass
Affected Versions node-forge versions prior to 1.3.2
Attack Vector Malformed ASN.1 structures (PKCS#12, certificates, signed messages)
Privileges Depends on application context (no native privileges required for exploit)
Impact Cryptographic verification bypass, signature/certificate acceptance issues

Technical Details

  • The flaw resides in node-forge's asn1.validate(...) traversal logic. When optional ASN.1 fields are manipulated, the validator can become desynchronized.
  • Desynchronization can cause the parser to skip required fields or misinterpret subsequent elements, allowing malformed structures to be treated as valid.
  • Demonstrated exploit: a tampered PKCS#12 archive where MAC verification fails but node-forge reports success.
  • Root cause fixed by tightening validation logic and correcting ASN.1 traversal/length handling in the 1.3.2 patch.

Attack Scenario

  1. Attacker crafts a malicious ASN.1 payload (e.g., PKCS#12, certificate, or signed message) that abuses optional fields to desynchronize the validator.
  2. The malicious object is supplied to an application that uses node-forge for verification (upload, authentication, or package verification).
  3. node-forge's asn1.validate(...) accepts the malformed structure as valid.
  4. The application skips integrity/MAC/signature checks or treats the tampered object as authentic.
  5. Attacker gains ability to load forged credentials, impersonate identities, bypass integrity checks, or run modified encrypted packages undetected.

Impact Assessment

  • High risk of signature or MAC verification bypass.
  • Applications may accept forged certificates, PKCS#12 archives, or signed payloads.
  • Potential account takeover where PKCS#12 or certificate-based auth is used.
  • Forged credentials could enable lateral access or impersonation.
  • Tampered encrypted configuration files or install packages may be accepted.
  • Downstream JavaScript apps and bundled codebases are at risk if they include vulnerable node-forge.

Mitigations

📦 Upgrade

  • Upgrade node-forge to version 1.3.2 or later (patch tightens ASN.1 validation).

🛠️ Build & Dependency Hygiene

  • Rebuild applications and audit bundled dependencies to ensure no residual vulnerable copies remain (npm ls node-forge).
  • Use SCA tools and dependency monitoring to detect vulnerable transitive dependencies.

🔐 Defense-in-Depth

  • Where possible, validate certificates and PKCS#12 using platform/native crypto libraries (OpenSSL, OS trust stores) in addition to node-forge.
  • Reject inputs that fail parsing or produce unexpected ASN.1 structures rather than attempting lenient recovery.

🔎 Incident Response

  • Regenerate PKCS#12 archives and certificates if tampering is suspected.
  • Hunt for unexpected successful verifications, unexpected certificate chains, or systems that accepted malformed packages.

Resources & References

Advisories & Coverage