CVE-2026-10566: FoundationAgents MetaGPT Deserialization Through Flawed Argument Mapping Vulnerability

LOW
Advisory Identifier: GHSA-3c3g-7hwg-9qmr
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CVSS 5.3
CWE-20
Published
Advisory Summary

CVE-2026-10566 is a LOW (CVSS 5.3) deserialization through flawed argument mapping vulnerability (CWE-20: Improper Input Validation) affecting FoundationAgents MetaGPT libraries in the PyPI ecosystem. The issue involves deserialization through flawed argument mapping via message.check_instruct_content(). Remediation is available in the latest vendor maintenance releases.

CVE-2026-10566 at a Glance

CVE Identifier CVE-2026-10566
GHSA Identifier GHSA-3c3g-7hwg-9qmr
Severity LOW
CVSS v3.1 Base Score 5.3
CWE Classification CWE-20: Improper Input Validation
Affected Product FoundationAgents MetaGPT
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L).

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability Low (A:L)

How to Fix CVE-2026-10566

To remediate this vulnerability, upgrade all affected FoundationAgents MetaGPT dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

metagpt fixed: Latest secure release 
pip install metagpt>=Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show metagpt

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-10566, inspect your installed packages using pip:

pip show metagpt

Analyze the terminal output to locate any version of FoundationAgents MetaGPT in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The pip show metagpt command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In FoundationAgents MetaGPT, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2026-10566 Affected FoundationAgents MetaGPT Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
metagpt
pypi/metagpt
PyPI
≤ 0.8.2

References

NVD — CVE-2026-10566 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-10566
FoundationAgents MetaGPT Source Repository REPOSITORY
https://github.com/FoundationAgents/MetaGPT/issues/2038
FoundationAgents MetaGPT Source Repository REPOSITORY
https://github.com/FoundationAgents/MetaGPT
vuldb.com/cve/cve-2026-10566 WEB
https://vuldb.com/cve/CVE-2026-10566
vuldb.com/submit/828301 WEB
https://vuldb.com/submit/828301
vuldb.com/vuln/367673 WEB
https://vuldb.com/vuln/367673
vuldb.com/vuln/367673/cti WEB
https://vuldb.com/vuln/367673/cti

Frequently Asked Questions

What is CVE-2026-10566?
CVE-2026-10566 is a security vulnerability in FoundationAgents MetaGPT involving Deserialization through flawed argument mapping via Message.check_instruct_content() under CWE-20: Improper Input Validation.
Which FoundationAgents MetaGPT versions are affected?
Affected versions include releases prior to current release patches across affected packages: metagpt.
What version fixes CVE-2026-10566?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is metagpt affected?
Yes, metagpt is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2026-10566?
CVE-2026-10566 has a CVSS v3.1 base score of 5.3 (LOW) with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L.
What CWE is associated with CVE-2026-10566?
CVE-2026-10566 is classified under CWE-20: Improper Input Validation (The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.).
How can I check PyPI dependencies for CVE-2026-10566?
Run the dependency tree command: 'pip show metagpt'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-3c3g-7hwg-9qmr",
  "modified" : "2026-07-09T13:44:24Z",
  "published" : "2026-06-02T03:31:26Z",
  "aliases" : [ "CVE-2026-10566" ],
  "summary" : " FoundationAgents MetaGPT: Deserialization through flawed argument mapping via Message.check_instruct_content()",
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L"
  }, {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "metagpt"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "0.8.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-10566"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FoundationAgents/MetaGPT/issues/2038"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/FoundationAgents/MetaGPT"
  }, {
    "type" : "WEB",
    "url" : "https://vuldb.com/cve/CVE-2026-10566"
  }, {
    "type" : "WEB",
    "url" : "https://vuldb.com/submit/828301"
  }, {
    "type" : "WEB",
    "url" : "https://vuldb.com/vuln/367673"
  }, {
    "type" : "WEB",
    "url" : "https://vuldb.com/vuln/367673/cti"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-09T13:44:24Z",
    "nvd_published_at" : "2026-06-02T03:16:16Z"
  }
}