Chainlit up to 2.9.3 /project/element chainlitKey path traversal

Summaryinfo

A vulnerability was found in Chainlit up to 2.9.3 and classified as critical. Affected is an unknown function of the file /project/element. Such manipulation of the argument chainlitKey leads to path traversal. This vulnerability is uniquely identified as CVE-2026-22218. The attack can be launched remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Chainlit up to 2.9.3. Affected by this issue is an unknown code of the file /project/element. The manipulation of the argument chainlitKey with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Impacted is confidentiality. CVE summarizes:

Chainlit versions prior to 2.9.4 contain an arbitrary file read vulnerability in the /project/element update flow. 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.

The weakness was disclosed by Ido Shani and Gal Zaban. The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-22218 since 01/06/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1006.

Upgrading to version 2.9.4 eliminates this vulnerability. The upgrade is hosted for download at github.com.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-3345). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Name

• Chainlit

Version

• 2.9.0
• 2.9.1
• 2.9.2
• 2.9.3

Website

• Product: https://github.com/Chainlit/chainlit/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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