Vulnerability · Published Oct 28, 2026 · Assigned by GitHub_M
CVE-2026-118668LangGraph JavaScript custom authentication may permit cross-user Store access
High 8.6
In plain English
A high-severity authorization bypass via user-controlled key in langgraph-api from langchain-ai. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | langgraph-api | 0.15.0 | GHSA-4hm6-w6qq-w73v |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| langchain-ai | langgraph-api | >= 0.1.2, < 0.15.0 |
Weakness: CWE-639, CWE-863 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N