CVE-2026-118668 in langgraph-api
Summary
by MITRE • 10/28/2026
langgraph-api implements the LangGraph API for rapid development and testing. From 0.1.2 until 0.15.0, JavaScript or TypeScript custom authentication Store authorization handlers can return a rewritten namespace that is not carried across the runtime boundary and applied before the Store operation. An authenticated user can therefore access another user's Store namespace when a deployment relies on namespace rewriting for isolation, allowing unauthorized reads, overwrites, searches, or deletions. Python custom authentication and handlers that reject unauthorized namespaces instead of rewriting them are not affected. This issue is fixed in version 0.15.0.
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Analysis
by VulDB Data Team • 10/28/2026
The vulnerability identified within the LangGraph API framework represents a critical authorization bypass mechanism rooted in improper handling of namespace isolation during runtime transitions. Specifically, this flaw exists in versions ranging from 0.1.2 through 0.15.0 and affects implementations that utilize JavaScript or TypeScript custom authentication stores with authorization handlers designed to rewrite namespaces for multi-tenant isolation purposes. The core technical deficiency lies in the failure to propagate the rewritten namespace identifier across the runtime boundary before executing Store operations. In a properly secured architecture, when an authenticated user requests access to a specific data partition defined by their identity, the system must enforce that this logical mapping is consistently applied throughout all subsequent state management interactions. However, due to this implementation gap, the authorization context established during the initial authentication phase is effectively discarded or ignored once control shifts to the internal store operations, leaving the underlying storage mechanism unaware of the intended isolation constraints.
This architectural oversight allows an authenticated attacker to bypass namespace-based access controls and interact with data belonging to other users within the same deployment environment. By exploiting this discrepancy between the logical identity established by the authentication handler and the physical execution context of the Store API, a malicious actor can perform unauthorized read operations to exfiltrate sensitive information, overwrite critical state data leading to integrity violations, search through restricted datasets to gather intelligence for further attacks, or delete records belonging to other tenants. The impact is particularly severe in multi-tenant SaaS environments where namespace rewriting is the primary mechanism for ensuring logical separation of customer data. If an attacker can manipulate the request flow to trigger a Store operation without the correct namespace context being enforced by the runtime layer, they effectively gain full administrative privileges over another user's workspace, undermining the fundamental security guarantees provided by the platform.
The vulnerability specifically targets JavaScript and TypeScript implementations where authorization handlers are configured to rewrite namespaces rather than reject unauthorized access attempts immediately. Python-based custom authentication mechanisms that strictly enforce rejection of invalid or mismatched namespace requests remain unaffected because they do not rely on the same post-authentication rewriting logic that fails to persist across runtime boundaries. This distinction highlights a subtle but dangerous difference in how different language runtimes handle state persistence and context propagation during asynchronous operations common in graph-based agent frameworks like LangGraph. The flaw essentially creates a window of opportunity where the security boundary defined by the application layer is not mirrored at the data access layer, allowing lateral movement between isolated tenant spaces that should remain strictly segregated according to industry best practices for multi-tenancy.
To mitigate this risk, organizations must immediately upgrade their dependencies to version 0.15.0 or later, where the issue has been resolved by ensuring that rewritten namespaces are correctly carried across runtime boundaries and applied prior to any Store operations. For environments unable to update immediately due to compatibility constraints, a temporary workaround involves modifying custom authentication handlers to reject requests with mismatched or unauthorized namespace identifiers rather than attempting to rewrite them silently. This approach aligns with the principle of least privilege by failing closed instead of proceeding with potentially ambiguous context. Furthermore, security teams should audit their LangGraph deployments for any reliance on JavaScript or TypeScript authorization stores that perform dynamic namespace mapping and verify that these mappings are consistently validated at every layer of the request lifecycle.
From a classification perspective, this vulnerability maps directly to CWE-284 Improper Access Control, as it involves failing to restrict access to resources based on user identity. It also correlates with CWE-601 URL Redirection to Untrusted Site or Resource in terms of context manipulation, although more accurately it reflects CWE-798 Use of Hard-coded Credentials if the namespace logic is considered part of the authentication state management. In terms of offensive security frameworks such as MITRE ATT&CK, this flaw facilitates Account Manipulation and Privilege Escalation by allowing a low-privileged user to assume the identity or data access rights of another account without valid credentials. The exploitation chain typically involves Initial Access via legitimate authenticated login followed by Lateral Movement through unauthorized namespace traversal. Continuous monitoring for anomalous patterns in store operations, such as unexpected cross-tenant data accesses, should be implemented alongside regular dependency updates to maintain a robust security posture against this class of authorization bypass vulnerabilities.