VU#521113 – Forge JavaScript ASN.1 Flaw Bypasses Signature Checks
Category:Vulnerabilities & Exploits
VU#521113 documents a vulnerability in the Forge JavaScript cryptography library (node-forge) that allows attackers to bypass signature verification via crafted ASN.1 structures. The flaw resides in the asn1.validate function, which can incorrectly treat tampered ASN.1 data as valid, particularly in fields like PKCS#12 Message Authentication Code (MAC) data, mapping to MITRE ATT&CK T1600 (Weaken Encryption) and T1553 (Subvert Trust Controls). Applications that rely on Forge to enforce the structure and integrity of X.509 certificates, PKCS#7 messages, or PKCS#12 archives may accept maliciously altered data as legitimate. By embedding custom options into certain ASN.1 fields that require recursive validation, an attacker can craft inputs that pass validation inspections despite being cryptographically incorrect. A proof-of-concept demonstrated how forged PKCS#12 MAC data could bypass verification, opening the door to authentication bypass, signed data tampering, or misuse of certificate-related operations. Because Forge is widely used in TLS utilities, certificate handling, and client-side cryptography, the vulnerable code path may appear in browsers, Node.js services, and custom cryptographic workflows. For organizations, the risk centers on trust decisions that depend on Forge for signature or integrity checks, such as validating software updates, tokens, certificates, or encrypted archives. If an attacker can supply crafted ASN.1 data to such a system, they may be able to impersonate trusted entities, accept forged content, or bypass integrity checks that guard code signing or secure communications. The severity depends on context, but in high-trust environments the potential impact is significant and may intersect with compliance obligations where cryptographic controls underpin regulatory requirements. The vulnerability is remediated in Forge version 1.3.2, which strengthens ASN.1 validation and includes targeted security tests for CVE-2025-12816. Developers should promptly upgrade dependencies, rebuild and redeploy affected services, and audit where Forge is used for critical signature verification. Security teams should update software composition analysis policies to flag outdated node-forge versions and consider defense-in-depth measures such as redundant verification using independent libraries for high-value trust anchors.
CORTEX Protocol Intelligence Assessment
Business Impact: VU#521113 threatens the integrity of cryptographic trust chains in applications that rely on Forge for certificate and signature validation. In sensitive environments, successful exploitation can lead to impersonation of trusted entities, acceptance of forged data, or bypass of code-signing protections that underpin software supply chain security. Technical Context: The vulnerability is a logic flaw in ASN.1 validation that allows tampered structures to pass signature checks, mapped to T1600 and T1553. It affects node-forge and downstream consumers until updated to version 1.3.2 or later, requiring dependency updates and renewed focus on how applications process untrusted ASN.1 inputs.
Strategic Intelligence Guidance
- Inventory all applications and services that depend on Forge or node-forge and upgrade to version 1.3.2 or later, then redeploy affected components.
- Implement software composition analysis in CI/CD pipelines to block builds that include vulnerable cryptographic libraries and enforce minimum version baselines.
- For high-trust use cases like code signing, certificate validation, and secure update mechanisms, consider implementing redundant verification with an independent crypto library.
- Strategically review threat models for cryptographic components and update secure coding standards to reinforce safe parsing and validation of untrusted ASN.1 and certificate data.
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Intelligence Source: VU#521113 – Forge JavaScript ASN.1 Flaw Bypasses Signature Checks | Nov 26, 2025