{"id":"CVE-2026-55235","summary":"langgraph-api: Relative webhook targets in LangGraph Server can reach in-process routes without authentication","details":"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.","aliases":["GHSA-2c9q-c2q9-qgqv","PYSEC-2026-3857"],"modified":"2026-09-16T03:46:57.273291096Z","published":"2026-09-14T15:53:19.013Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55235.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-287"]},"references":[{"type":"WEB","url":"https://github.com/langchain-ai/docs/blob/7b70fbacab21f84d9c6f9848f86cdeb471adbb50/src/langsmith/agent-server-changelog.mdx"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55235.json"},{"type":"ADVISORY","url":"https://github.com/langchain-ai/helm/security/advisories/GHSA-2c9q-c2q9-qgqv"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55235"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/langchain-ai/helm","events":[{"introduced":"0"},{"fixed":"bf062198cd5a9fe23a3e71c057a2103738ec3724"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"0.10.0"}],"source":"AFFECTED_FIELD"}}],"versions":["langsmith-0.8.28","langsmith-0.9.39","langgraph-dataplane-0.1.7","langsmith-0.9.37","langgraph-operator-0.1.10","langsmith-0.9.36","langsmith-0.9.35","langgraph-dataplane-0.1.6","langsmith-0.9.34","langgraph-operator-0.1.9","langgraph-dataplane-0.1.5","langsmith-0.9.33","langgraph-dataplane-0.1.4","langsmith-0.9.32","langsmith-0.9.31","langgraph-dataplane-0.1.3","langgraph-operator-0.1.8","langgraph-operator-0.1.7","langgraph-operator-0.1.6","langsmith-0.9.30","langgraph-dataplane-0.1.2","langgraph-dataplane-0.1.1","langgraph-operator-0.1.5","langgraph-cloud-0.1.12","langsmith-0.9.29","langsmith-0.9.28","langgraph-operator-0.1.4","langsmith-0.9.27","langsmith-0.9.26","langgraph-operator-0.1.3","langsmith-0.9.25","langgraph-operator-0.1.2","langgraph-operator-0.1.1","langgraph-operator-0.1.0","langsmith-0.9.24","langgraph-dataplane-0.1.0","langsmith-0.9.23","langsmith-0.9.22","langsmith-0.9.21","langgraph-cloud-0.1.11","langsmith-0.9.20","langsmith-0.9.19","langgraph-cloud-0.1.10","langgraph-cloud-0.1.9","langsmith-0.9.18","langgraph-cloud-0.1.8","langgraph-cloud-0.1.7","langsmith-0.9.17","langsmith-0.9.16","langsmith-0.9.15","langsmith-0.9.14","langsmith-0.9.13","langsmith-0.9.12","langsmith-0.9.11","langsmith-0.9.10","langsmith-0.9.9","langsmith-0.9.8","langsmith-0.9.7","langsmith-0.9.6","langsmith-0.9.5","langsmith-0.9.4","langgraph-cloud-0.1.6","langsmith-0.9.3","langsmith-0.9.2","langsmith-0.9.1","langsmith-0.9.0","langsmith-0.8.27","langsmith-0.8.26","langsmith-0.8.25","langsmith-0.8.24","langsmith-0.8.23","langsmith-0.8.22","langsmith-0.8.21","langsmith-0.8.20","langsmith-0.8.19","langsmith-0.8.18","langsmith-0.8.17","langsmith-0.8.16","langgraph-cloud-0.1.5","langsmith-0.8.15","langsmith-0.8.14","langsmith-0.8.13","langsmith-0.8.12","langsmith-0.8.11","langsmith-0.8.10","langsmith-0.8.9","langsmith-0.8.8","langsmith-0.8.7","langsmith-0.8.6","langsmith-0.8.5","langsmith-0.8.4","langsmith-0.8.3","langsmith-0.8.2","langsmith-0.8.1","langsmith-0.8.0","langsmith-0.7.11","langsmith-0.7.10","langsmith-0.7.9","langsmith-0.7.8","langsmith-0.7.7","langsmith-0.7.6","langsmith-0.7.5","langgraph-cloud-0.1.4","langsmith-0.7.4","langsmith-0.7.3","langgraph-cloud-0.1.3","langsmith-0.7.2","langsmith-0.7.1","langsmith-0.7.0","langsmith-0.6.24","langsmith-0.6.23","langsmith-0.6.22","langsmith-0.6.21","langsmith-0.6.20","langsmith-0.6.19","langsmith-0.6.18","langsmith-0.6.17","langsmith-0.6.16","langsmith-0.6.15","langsmith-0.6.14","langsmith-0.6.13","langsmith-0.6.12","langsmith-0.6.11","langsmith-0.6.10","langsmith-0.6.9","langsmith-0.6.8","langsmith-0.6.7","langgraph-cloud-0.1.2","langsmith-0.6.6","langgraph-cloud-0.1.1","langgraph-cloud-0.1.0","langsmith-0.6.5","langsmith-0.6.4","langsmith-0.6.3","langsmith-0.6.2","langsmith-0.6.1","langsmith-0.5.4","langsmith-0.5.3","langsmith-0.5.2","langsmith-0.5.1","langsmith-0.5.0","langsmith-0.4.7","langsmith-0.4.6","langsmith-0.4.5","langsmith-0.4.4","langsmith-0.4.3","langsmith-0.4.2","langsmith-0.4.1","langsmith-0.4.0","langsmith-0.3.9","langsmith-0.3.8","langsmith-0.3.7","langsmith-0.3.6","langsmith-0.3.5","langsmith-0.3.4","langsmith-0.3.3","langsmith-0.3.2","langsmith-0.3.1","open-gpts-0.1.2","langsmith-0.2.11","langsmith-0.2.10","langsmith-0.2.9","open-gpts-0.1.1","open-gpts-0.1.0","langsmith-0.2.8","langsmith-0.2.7","langsmith-0.2.6","langsmith-0.2.5","langsmith-0.2.4","langsmith-0.2.3","langsmith-0.2.2","langsmith-0.2.1","langsmith-0.2.0","langsmith-0.1.16","langsmith-0.1.15","langsmith-0.1.14","langsmith-0.1.13","langsmith-0.1.12","langsmith-0.1.11","langsmith-0.1.10","langsmith-0.1.9","langsmith-0.1.8","langsmith-0.1.7","langsmith-0.1.6","langsmith-0.1.5","langsmith-0.1.4","langsmith-0.1.3","langsmith-0.1.2","langsmith-0.1.1","langsmith-0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55235.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L"}]}