Critical Auth Bypass in MomentumDB (CVE-2025-31207)

A critical authentication bypass vulnerability has been discovered in the MomentumDB in-memory database platform. Tracked as CVE-2025-31207, this flaw allows a remote, unauthenticated attacker to gain full administrative access to the database. This vulnerability has a CVSS score of 9.8 (Critical) and requires immediate action.

TL;DR:

• What: A critical authentication bypass vulnerability due to a type juggling flaw.
• Affected Software: MomentumDB versions 3.1.0 through 3.4.1.
• Impact: An attacker can gain full administrative access to the database, allowing them to read, modify, and delete all data.
• Action: Update to version 3.4.2 or newer immediately.

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What is MomentumDB?

MomentumDB is a high-performance, in-memory NoSQL database designed for real-time applications, caching, and session management. It’s known for its speed and is often used to store critical application data.

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The Vulnerability: Type Juggling Leads to Auth Bypass

The vulnerability lies in how the MomentumDB management API validates authentication tokens. The code used a loose comparison (==) instead of a strict comparison (===) to check the provided token against the stored token hash.

This becomes a critical issue due to a behavior in some programming languages known as “type juggling.” When a string that looks like a number in scientific notation (e.g., "0e8324521") is loosely compared to an integer (e.g., 0), the language may evaluate them as equal.

Many hashing algorithms (like MD5 or older SHA1) can produce hashes that happen to start with "0e" followed by only digits.

The Attack:

1. An attacker identifies a MomentumDB instance where the real API token hash starts with "0e".
2. The attacker sends an authentication request with the integer 0 as their API token.
3. The vulnerable server code performs a loose comparison: if ("0e8324521..." == 0).
4. Due to type juggling, this statement evaluates to true, and the server grants the attacker full administrative access.

Here’s a pseudo-code example of the flawed logic:

JavaScript

// Vulnerable code in MomentumDB < 3.4.2
function authenticate(provided_token) {
  const stored_hash = getStoredTokenHash(); // e.g., "0e8324521..."

  // The loose comparison '==' is the flaw.
  // This evaluates to TRUE if provided_token is 0.
  if (stored_hash == provided_token) {
    return "Authentication successful!";
  }
  return "Authentication failed.";
}

This simple flaw completely breaks the authentication mechanism under the right conditions.

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Impact and Remediation

The impact of CVE-2025-31207 is catastrophic for anyone using a vulnerable version. A successful attacker can:

• Read all data stored in the database, including user PII, session data, and application secrets.
• Modify or corrupt data, leading to application failure and data integrity issues.
• Delete the entire database, causing a complete denial of service.

Are you affected? You are vulnerable if you are running MomentumDB versions 3.1.0 through 3.4.1.

How to Fix It 🛡️ The MomentumDB team has issued a security release that resolves this issue by replacing the loose comparison operator with a strict one.

1. Update Immediately: Upgrade your MomentumDB instances to the patched version 3.4.2 or newer. This is the only way to fully remediate the vulnerability.
2. Regenerate API Tokens: As a precaution, you should rotate all API tokens after performing the update.
3. Review Access Logs: Check your MomentumDB access logs for any suspicious authentication patterns, such as repeated attempts with simple integer values.

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Resources and Citations

• Official MomentumDB Website: https://momentumdb.io
• Official GitHub Repository: https://github.com/MomentumData/MomentumDB
• Official Security Advisory: https://github.com/MomentumData/MomentumDB/security/advisories/GHSA-fictional-abcd-5678
• NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2025-31207
• Discoverer’s Technical Blog Post: https://www.zerodayinitiative.com/blog/2025/8/12/type-juggling-and-auth-bypass-in-momentumdb