{"id":"CVE-2026-55235","title":"langgraph-api implements the LangGraph API for rapid development and testing","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 a…","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L","cwe":["CWE-287"],"vendor":"langgraph-api","product":"langgraph-api","affected":["langgraph-api < 0.10.0"],"patched":["langgraph-api 0.10.0"],"published":"2026-09-14","updated":"2026-09-16","sourceUpdated":"2026-09-16T16:17:09.373","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55235","references":[{"url":"https://github.com/langchain-ai/docs/blob/7b70fbacab21f84d9c6f9848f86cdeb471adbb50/src/langsmith/agent-server-changelog.mdx","label":"security-advisories@github.com"},{"url":"https://github.com/langchain-ai/helm/security/advisories/GHSA-2c9q-c2q9-qgqv","label":"security-advisories@github.com"},{"url":"https://github.com/langchain-ai/helm"},{"url":"https://pypi.org/project/langgraph-api"},{"url":"https://github.com/advisories/GHSA-2c9q-c2q9-qgqv"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55235"}],"tags":["nvd","osv","pip","cve.org"],"epss":0.00234,"epssPercentile":0.14614,"aliases":["GHSA-2c9q-c2q9-qgqv","PYSEC-2026-3857"],"ecosystem":"pip","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-16T15:14:41.906689Z"},"ingestedAt":"2026-08-19T19:22:18.276Z","slug":"CVE-2026-55235","body":"## Overview\n\nlanggraph-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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-55235)\n\nAffected packages:\n\n- `langgraph-api < 0.10.0`\n\nPatched in:\n\n- `langgraph-api 0.10.0`\n\nSource: https://osv.dev/vulnerability/GHSA-2c9q-c2q9-qgqv","depth":"sunlit","depthScore":32,"depthScoreParts":{"impact":32.5,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}