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CVE-2026-55235GHSA-2C9Q-C2Q9-QGQVPYSEC-2026-3857

langgraph-api: Relative webhook targets in LangGraph Server can reach in-process routes without authentication

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 0.10.0
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

langgraph-api implements the LangGraph API for rapid development and testing. Prior to 0.10.0, langgraph-api permits a run or cron to specify a relative webhook target that is delivered through an in-process loopback transport, and the authentication middleware treats that transport as internal without applying the authentication context used for external requests. In deployments that rely on per-user authorization to separate threads and runs, an authenticated user can direct a webhook to the server's own thread and run routes, allowing creation of a run on or modification of another user's thread and limited incorporation of the targeted thread's metadata into the created run record. The affected path requires webhook targets and per-user authorization boundaries; deployments that deliberately re-enable loopback delivery should restrict it to controlled same-process routes because those webhooks remain unauthenticated. This issue is fixed in version 0.10.0.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • langchain-ai langgraph-api

    fixed in 0.10.0

  • langgraph-apiPyPI

    fixed in 0.10.0

References 2

GitHub · langchain-ai/helm

GitHub · langchain-ai/docs