CVE-2026-118668
Description
A flaw was found in langgraph-api. In deployments using JavaScript or TypeScript custom authorization handlers, rewritten storage namespaces intended to isolate tenant data are not properly enforced across the runtime boundary before storage operations execute. An authenticated remote attacker can exploit this vulnerability to access another user's storage namespace, resulting in unauthorized data disclosure, modification, or deletion.
Statement
This vulnerability is rated as Important because authenticated remote users can bypass multi-tenant isolation to access, alter, or remove other users' stored data without requiring administrative privileges. Exploitation requires multi-user environments configured with custom JavaScript or TypeScript Store authorization handlers that depend on namespace rewriting for tenant segregation. Systems utilizing standard Python-based authentication or authorization logic that rejects unauthorized access rather than rewriting namespaces are not vulnerable to this issue.
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
Access control checks for specific user data or functionality can be bypassed.
Access Control
Technical Impact: Gain Privileges or Assume Identity
Horizontal escalation of privilege is possible (one user can view/modify information of another user).
Access Control
Technical Impact: Gain Privileges or Assume Identity
Vertical escalation of privilege is possible if the user-controlled key is actually a flag that indicates administrator status, allowing the attacker to gain administrative access.
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