CVE-2026-118667

Name of the Vulnerable Software and Affected Versions langgraph-sdk versions 0.4.0 through 0.4.5 langgraph versions 1.2.3 through 1.2.13

Description The LangGraph Python SDK v3 streaming client fails to encode caller-supplied thread id and assistant id values when interpolating them into request paths within the synchronous and asynchronous get tree() and fetch state() helpers. Because these identifiers are not processed through the quote path param helper, relative path segments can be used to redirect authenticated GET requests to other readable paths on the configured server. An attacker providing controlled text for these variables can cause the SDK to return responses from different server paths, including the ability to control the query string via thread id. This issue does not allow for write operations as it is limited to GET requests.

Recommendations Upgrade langgraph-sdk to version 0.4.6 or later. Upgrade langgraph to version 1.2.14 or later.