CVE-2026-22218 Chainlit CVE debrief

Who should care

Users of Chainlit versions prior to 2.9.4 should apply the patch to prevent unauthorized file disclosure. This includes administrators and security teams responsible for maintaining Chainlit instances, as well as developers who use Chainlit in their applications.

Technical summary

The vulnerability exists in the /project/element update flow of Chainlit. An authenticated client can send a custom Element with a user-controlled path value, causing the server to copy the referenced file into the attacker’s session. The resulting element identifier (chainlitKey) can then be used to retrieve the file contents via /project/file/<chainlitKey>, allowing disclosure of any file readable by the Chainlit service. This issue is particularly concerning because it allows for the potential disclosure of sensitive files.

Defensive priority

High

Recommended defensive actions

• Apply the patch to upgrade Chainlit to version 2.9.4 or later.
• Restrict access to the /project/element update flow and /project/file/ endpoints.
• Monitor for suspicious activity on the Chainlit service.
• Perform regular inventory checks to ensure all Chainlit instances are up-to-date.
• Implement compensating controls, such as file access controls and monitoring.
• Review and update security configurations to prevent similar vulnerabilities.
• Conduct a thorough review of the Chainlit service to identify potential security risks.

Evidence notes

The CVE record was published on 2026-01-20T00:15:48.910Z and has not been modified since then. The NVD entry is currently Analyzed. There are no additional details available beyond what is provided in the CVE record and NVD entry.

Official resources