CVE-2026-118667 is a medium-severity (CVSS 4.3) Path Traversal vulnerability in langgraph-sdk. A fix is available for langgraph-sdk — see the affected versions and patch details below.
LangGraph: Unencoded identifiers in LangGraph SDK v3 streaming can redirect authenticated GET requests
Real-World Exposure
langgraph-sdk🐍langgraphReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
The LangGraph Python SDK v3 streaming client interpolates caller-supplied thread_id and assistant_id 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 get_tree and _fetch_state implementations build request paths from raw identifiers rather than passing each identifier through the SDK's existing _quote_path_param 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"]["thread_id"] 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 thread_id or assistant_id. In that configuration, an attacker may select another readable path on the configured server and cause the SDK to return that response to the application. Through thread_id, the attacker can also control the query string, for example by targeting /store/items?namespace=...&key=...; assistant_id controls only the path. The affected requests are GET operations, so this issue does not provide a write primitive.
The LangGraph Platform is not exposed to this issue.
Remediation
Upgrade langgraph-sdk to version 0.4.6 or later. The fix encodes assistant_id in get_tree and thread_id in _fetch_state with _quote_path_param in both synchronous and asynchronous stream modules.
If you use RemoteGraph, also upgrade langgraph to version 1.2.14 or later, which requires langgraph-sdk>=0.4.6.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | langgraph-sdk | ≥ 0.4.0&&< 0.4.6 | 0.4.6pip install --upgrade 'langgraph-sdk==0.4.6' |
| 🐍PyPI | langgraph | ≥ 1.2.3&&< 1.2.14 | 1.2.14pip install --upgrade 'langgraph==1.2.14' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for langgraph-sdk, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update langgraph-sdk to 0.4.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-118667 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
Frequently Asked Questions
Is CVE-2026-118667 in your dependencies?
Find it across PyPI, including transitive dependencies.