Unencoded identifiers in LangGraph SDK v3 streaming can redirect authenticated GET requests

The LangGraph security advisory (GHSA-3fx2-cqw9-xr3c, CVE-2026-118667) discloses a vulnerability in its Python SDK v3 streaming client: caller-provided thread_id and assistant_id are concatenated unencoded into the request path at four sync and async call sites, and values containing relative path segments can, via HTTP path normalization, redirect an authenticated GET request to other paths on the same configured server while retaining the client's authentication headers. Versions of langgraph-sdk before 0.4.6 are affected and it has been fixed in 0.4.6; when used with the vulnerable SDK, the RemoteGraph v3 streaming feature in langgraph versions before 1.2.14 is also affected and has been fixed in 1.2.14. The fix is to upgrade langgraph-sdk to 0.4.6 or higher; those using RemoteGraph must also upgrade langgraph to 1.2.14 or higher.