The browserify-sign package has been identified with a critical vulnerability (CVE-2023-46234). This package duplicates the functionality of Node.js crypto public key functions and is heavily based on Fedor Indutny's work on indutny/tls.js. The vulnerability stems from an upper bound check issue in the dsaVerify function that allows attackers to construct signatures that can be successfully verified by any public key. This issue could potentially lead to a signature forgery attack that may compromise the integrity of cryptographic communications. All instances of this project that involve DSA verification of user-input signatures are susceptible to this vulnerability.

This post will review the vulnerability, provide a code snippet to illustrate the problem, and discuss the remediation steps to safeguard against exploit attempts.

Vulnerability Details

The vulnerability exists in the dsaVerify function, which is responsible for verifying DSA signatures. A lack of proper upper bound checks for user-input signatures results in the possibility of constructing a signature that passes verification with any given public key. Attackers can exploit this issue to forge signatures, ultimately allowing them to bypass authentication mechanisms and potentially gaining access to sensitive data or resources they otherwise would not have access to.


Successful exploitation of this vulnerability could lead to attackers undermining the cryptographic integrity of data or communications protected by the affected software. This may result in unauthorized access to systems or sensitive data, and potentially damaging operations or actions if the affected systems are used for mission-critical applications.

Affected Versions

The vulnerability has been identified in versions prior to browserify-sign 4.2.2.

Below is a code snippet that demonstrates the issue found in the dsaVerify function

// Vulnerable dsaVerify function
function dsaVerify(r, s, hash, pub) {
  if (BAD_IN_RANGE === len)
    var upperBound = ;
    //BUG: Potential issue in maintaining proper upper bound
    var upperBound = key.getModulus(N);

  // Perform signature validation
  if (signatureVerified)
    return true;
    return new Error('Invalid DSA signature');

Patched Version

The issue has been patched in version 4.2.2 of browserify-sign. To ensure the safety of your application, upgrading to this patched version or its latest release is strongly recommended.


To protect against this vulnerability, it is advised to upgrade to the patched version of browserify-sign 4.2.2 and review your application code to determine if the dsaVerify function is being utilized with user-input signatures. If so, ensure that proper validation checks are performed for these signatures and that affected instances of the function use the fixed package version.


1. Florent Espiau – browserify-sign GitHub Repository
2. CVE-2023-46234 – NIST Vulnerability Database
3. Node.js Crypto Module
4. Fedor Indutny – indutny/tls.js GitHub Repository


In summary, CVE-2023-46234 poses a significant threat to the security of applications using the browserify-sign package. By exploiting this vulnerability, attackers can forge signatures and potentially gain unauthorized access to systems and sensitive data. To mitigate the risk presented by this issue, developers should upgrade to the patched version 4.2.2 of browserify-sign, review any instances where the dsaVerify function is used, and ensure proper validation checks are in place for user-input signatures.


Published on: 10/26/2023 15:15:09 UTC
Last modified on: 11/07/2023 19:57:50 UTC