CVE-2022-21671: Potential exposure of Replit tokens to an Unauthorized Actor in @replit/crosis

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-01-11 · updated 2026-06-17
Weakness: CWE-200

Description

@replit/crosis is a JavaScript client that speaks Replit's container protocol. A vulnerability that involves exposure of sensitive information exists in versions prior to 7.3.1. 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). This was patched in version 7.3.1 by updating the address of the fallback WebSocket polling proxy to the new one. As a workaround, a user may specify the new address for the polling host (`gp-v2.replit.com`) in the `ConnectArgs`. More information about this workaround is available in the GitHub Security Advisory.

Affected products

replit crosis: before 7.3.1 — fixed in 7.3.1

How to fix

Upgrade to a fixed version: replit crosis 7.3.1. Check the vendor advisory for mitigations.

References

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