LangGraph: Unencoded identifiers in LangGraph SDK v3 streaming can redirect authenticated GET requests
CVE-2026-118667
Summary The LangGraph Python SDK v3 streaming client interpolates caller-supplied threadid and assistantid values into request paths without encoding them at four synchronous and asynchronous call sites. Relative path segments can therefore redirect an authenticated GET request to another path on the same configured server. Details The affected gettree and fetchstate implementations build request paths from raw identifiers rather than passing each identifier through the SDK's existing quotepathparam helper. HTTP path normalization can collapse values containing relative segments before dispatch while retaining the client's authentication headers. langgraph-sdk versions 0.4.0 through 0.4.5 are affected. The v3 stream module is not present in the 0.3.x release line. RemoteGraph v3 streaming in langgraph 1.2.3 and later is also affected when used with a vulnerable langgraph-sdk version. It passes config["configurable"]["threadid"] into threads.stream(...), and its dependency range permits affected SDK versions. Impact An application is affected only if it passes attacker-controlled text as a streaming threadid or assistantid. In that configuration, an attacker may select another…
Assessment
- CVSS
- 4.3 (v3.1)
- Severity
- Medium
- EPSS
- 0.00394% chance of exploitation in the next 30 days
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 28 October 2026
- Last updated
- 28 October 2026
- Affected
- pip · langgraph-sdk, langgraph
- Weakness
- CWE-22
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
At the source
References
- https://github.com/langchain-ai/langgraph/security/advisories/GHSA-3fx2-cqw9-xr3c
- https://github.com/langchain-ai/langgraph/pull/9213
- https://github.com/langchain-ai/langgraph/commit/d89c7e100ec6fc1512544d23b0a7c5169699ef3e
- https://github.com/langchain-ai/langgraph/releases/tag/1.2.14
- https://github.com/langchain-ai/langgraph/releases/tag/sdk%3D%3D0.4.6
- https://github.com/advisories/GHSA-3fx2-cqw9-xr3c
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