{"cve":"CVE-2026-55235","nvd":{"published":"2026-09-14T16:17:12.513","modified":"2026-09-30T17:51:56.193","status":"Deferred","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L","score":5.9},"cwes":["CWE-287"],"references":["https://github.com/langchain-ai/docs/blob/7b70fbacab21f84d9c6f9848f86cdeb471adbb50/src/langsmith/agent-server-changelog.mdx","https://github.com/langchain-ai/helm/security/advisories/GHSA-2c9q-c2q9-qgqv"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-55235","score":0.00365,"percentile":0.30045,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-2c9q-c2q9-qgqv","url":"https://osv.dev/vulnerability/GHSA-2c9q-c2q9-qgqv","summary":"langgraph-api: Relative webhook targets in LangGraph Server can reach in-process routes without authentication","modified":"2026-09-10T12:26:06.320381460Z","packages":[{"ecosystem":"PyPI","name":"langgraph-api","purl":"pkg:pypi/langgraph-api","ranges":["<0.10.0"],"fixed":["0.10.0"]}]},{"id":"PYSEC-2026-3857","url":"https://osv.dev/vulnerability/PYSEC-2026-3857","summary":"langgraph-api: Relative webhook targets in LangGraph Server can reach in-process routes without authentication","modified":"2026-09-10T12:15:09.104854079Z","packages":[{"ecosystem":"PyPI","name":"langgraph-api","purl":"pkg:pypi/langgraph-api","ranges":["<0.10.0"],"fixed":["0.10.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}