CVE-2026-118667: LangGraph: Unencoded identifiers in LangGraph SDK v3 streaming can redirect authenticated GET requests

Description

LangGraph Python SDK is used to connect to running LangGraph API servers, manage assistants, threads and stream runs from Python applications. From langgraph-sdk 0.4.0 until 0.4.6, and from langgraph 1.2.3 until 1.2.14 when RemoteGraph v3 streaming uses an affected langgraph-sdk version, the synchronous and asynchronous v3 stream get_tree and _fetch_state helpers interpolate caller-controlled assistant_id and thread_id values into authenticated GET request paths without using _quote_path_param. Relative path segments can therefore be normalized into another readable path on the configured server while retaining authentication headers. This issue is fixed in langgraph-sdk 0.4.6 and langgraph 1.2.14.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Attack vector

Network

Complexity

Low

Privileges

Low

User interaction

None

Confidentiality

Low

Integrity

None

Availability

None

Scope

Unchanged

Exploitation

Is it being used?

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

LA

langgraph · langchain-ai

>= 1.2.3, < 1.2.14 · source: vendor

LA

langgraph-sdk · langchain-ai

>= 0.4.0, < 0.4.6 · source: vendor