CVE-2022-21671

Potential exposure of tokens to an Unauthorized Actor

Workarounds

Specify the new address for the polling host (gp-v2.replit.com) in the ConnectArgs:

const connectOptions: ConnectArgs = {
  // ...
  pollingHost: 'gp-v2.replit.com',
};
client.connect(connectOptions);

For more information

Thanks to https://hackerone.com/orlserg for disclosing this.

If you have any questions or comments about this advisory:

• Open an issue in replit/crosis
• Email us at [email protected]

When using this library as a way to programmatically communicate with Replit in a standalone fashion, if there are multiple failed attempts to contact Replit through a WebSocket, the library will attempt to communicate using a fallback poll-based proxy. The URL of the proxy has changed, so any communication done to the previous URL could potentially reach a server that is outside of Replit's control and the token used to connect to the Repl could be obtained by an attacker, leading to full compromise of that Repl (not of the account).

CVE-2022-21671 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (7.3.1); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

This was patched in 7.3.1, by updating the address of the fallback WebSocket polling proxy to the new one.

1. What is CVE-2022-21671? CVE-2022-21671 is a medium-severity security vulnerability in @replit/crosis (npm), affecting versions < 7.3.1. It is fixed in 7.3.1.
2. How severe is CVE-2022-21671? CVE-2022-21671 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of @replit/crosis are affected by CVE-2022-21671? @replit/crosis (npm) versions < 7.3.1 is affected.
4. Is there a fix for CVE-2022-21671? Yes. CVE-2022-21671 is fixed in 7.3.1. Upgrade to this version or later.
5. Is CVE-2022-21671 exploitable, and should I be worried? Whether CVE-2022-21671 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2022-21671 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2022-21671? Upgrade @replit/crosis to 7.3.1 or later.