{"id":"CVE-2026-55235","state":"PUBLISHED","title":"langgraph-api: Relative webhook targets in LangGraph Server can reach in-process routes without authentication","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.","publishedAt":"2026-09-14T15:53:19.013Z","updatedAt":"2026-09-16T15:14:55.630Z","severity":{"score":5.9,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["langchain-ai langgraph-api"],"affected":[{"vendor":"langchain-ai","product":"langgraph-api","versions":[{"version":"< 0.10.0","status":"affected"}]}],"references":["https://github.com/langchain-ai/helm/security/advisories/GHSA-2c9q-c2q9-qgqv","https://github.com/langchain-ai/docs/blob/7b70fbacab21f84d9c6f9848f86cdeb471adbb50/src/langsmith/agent-server-changelog.mdx"],"weaknesses":["CWE-287"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55235.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55235","state":"PUBLISHED","datePublished":"2026-09-14T15:53:19.013Z","dateUpdated":"2026-09-16T15:14:55.630Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-16T16:44:00.623Z"},"containers":{"cna":{"title":"langgraph-api: Relative webhook targets in LangGraph Server can reach in-process routes without authentication","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"langchain-ai","product":"langgraph-api","versions":[{"version":"< 0.10.0","status":"affected"}]}],"references":[{"url":"https://github.com/langchain-ai/helm/security/advisories/GHSA-2c9q-c2q9-qgqv","name":"https://github.com/langchain-ai/helm/security/advisories/GHSA-2c9q-c2q9-qgqv","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/langchain-ai/docs/blob/7b70fbacab21f84d9c6f9848f86cdeb471adbb50/src/langsmith/agent-server-changelog.mdx","name":"https://github.com/langchain-ai/docs/blob/7b70fbacab21f84d9c6f9848f86cdeb471adbb50/src/langsmith/agent-server-changelog.mdx","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":5.9,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-287","lang":"en","description":"CWE-287: Improper Authentication","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-14T15:53:19.013Z"},"source":{"advisory":"GHSA-2c9q-c2q9-qgqv","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-16T15:14:41.906689Z","id":"CVE-2026-55235","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-16T15:14:55.630Z"}}]}}}