CVE-2026-118667

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

MEDIUM
4.3
CVSS Score
Published: October 28, 2026 at 08:51 PM UTC
Updated: October 29, 2026 at 07:17 PM UTC
2 products affected across 1 vendorLangGraphLangGraph SDK

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Severity
MEDIUM4.3
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

1.2.3 ≤ v < 1.2.141.2.3
0.4.0 ≤ v < 0.4.60.4.0

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-22

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