A recently discovered vulnerability in the Node.js policy feature has been assigned the unique identifier CVE-2023-38552. The vulnerability allows an attacker to forge a fake checksum for a resource and bypass the integrity check mechanism, potentially leading to unauthorized access or modification of data.


Node.js is a popular JavaScript runtime built on Chrome's V8 JavaScript engine. It allows developers to build scalable, high-performance applications with ease using JavaScript. One of the experimental features provided in Node.js is its policy mechanism, which enables developers to enforce specific rules and restrictions on their applications in a secure and standardized manner.

However, CVE-2023-38552 demonstrates a limitation in this policy mechanism, where it fails to ensure the integrity of a resource against a trusted manifest. Attackers can exploit this vulnerability to forge fake checksums and disrupt the normal functioning of the application.

Exploit Details

When the Node.js policy feature checks the integrity of a resource against a trusted manifest, the application can intercept the operation and return a forged checksum to the Node.js policy implementation. This process bypasses the integrity check and allows tampered or malicious resources to be loaded by the application.

Here's a code snippet demonstrating the vulnerability

// Original checksum in the trusted manifest
const originalChecksum = "9a34c582134d74dd56d816b3c882";

// Fake checksum that will be returned to the Node.js policy implementation
const fakeChecksum = "8e78fb24564d8365b98a12dc5b156";

// Function that intercepts the integrity check operation
function interceptIntegrityCheck() {
  // Bypass the actual integrity check by returning a fake checksum
  return fakeChecksum;

// Replacing the original integrity check function with the interceptor
NodeJsPolicyImplementation.integrityCheck = interceptIntegrityCheck;


This vulnerability affects all users who rely on the experimental policy mechanism in all active Node.js release lines: 18.x and 20.x.

However, it is essential to note that the policy mechanism is still an experimental feature in Node.js and is not considered stable. As a result, the risk of this vulnerability might not affect a majority of production systems.


As CVE-2023-38552 is a newly discovered vulnerability, developers should track the progress of the Node.js project to stay informed about any patches or updates that might address this issue. Furthermore, developers are encouraged to contribute to the project by reporting any potential vulnerabilities or submitting fixes.

In the meantime, developers who rely on the policy feature should carefully assess its use in their applications while considering the experimental nature of the policy mechanism.

Original References

The following links provide additional information about CVE-2023-38552 and its potential impact on the Node.js ecosystem:

1. Official Node.js GitHub Repository
2. CVE Details - CVE-2023-38552
3. Node.js Policy implementation documentation

In conclusion, developers should be vigilant when using experimental features in their applications. CVE-2023-38552 demonstrates that even trusted resources are not always exempt from vulnerabilities and can be exploited by malicious actors in unexpected ways. Always stay up-to-date with the latest patches and advisories to ensure your application's security and integrity.


Published on: 10/18/2023 04:15:11 UTC
Last modified on: 11/03/2023 22:15:09 UTC