CVE-2026-79408 Overview
CVE-2026-79408 is an operating system (OS) command injection vulnerability in MetaGPT version 0.8.1. The flaw resides in the RepoParser.rebuild_class_views() function within metagpt/repo_parser.py. An unauthenticated attacker can inject arbitrary shell commands through the path argument passed to this function. Successful exploitation results in arbitrary command execution in the context of the process running MetaGPT. The vulnerability is classified under [CWE-78] Improper Neutralization of Special Elements used in an OS Command.
Critical Impact
Attackers can execute arbitrary OS commands on hosts running MetaGPT 0.8.1, leading to full compromise of confidentiality, integrity, and availability.
Affected Products
- MetaGPT 0.8.1
- Applications embedding metagpt/repo_parser.py from the affected release
- Automated agent pipelines invoking RepoParser.rebuild_class_views() with untrusted input
Discovery Timeline
- 2026-08-31 - CVE-2026-79408 published to the National Vulnerability Database (NVD)
- 2026-09-01 - Last updated in NVD database
Technical Details for CVE-2026-79408
Vulnerability Analysis
MetaGPT is a multi-agent framework that automates software engineering workflows. The RepoParser component analyzes source repositories and rebuilds class relationship views. The rebuild_class_views() method accepts a path argument that identifies the repository location on disk.
The function passes this path argument into an OS command that is executed by the underlying shell. Because the input is not sanitized or properly quoted, attackers can append shell metacharacters such as ;, &&, |, or backticks. The injected payload runs with the privileges of the MetaGPT process.
This is a network-reachable issue when MetaGPT is exposed through an API, agent orchestrator, or web frontend that forwards user-controlled paths into RepoParser. No authentication or user interaction is required in that deployment pattern.
Root Cause
The root cause is the direct concatenation of untrusted input into a shell command string invoked by RepoParser.rebuild_class_views(). The implementation does not use safe process APIs, argument arrays, or input allow-listing. Any caller that forwards attacker-controlled data as the path parameter enables command injection.
Attack Vector
An attacker supplies a crafted path value containing shell separators followed by an arbitrary command. When rebuild_class_views() executes the constructed command line, the shell interprets the injected segment. The attack does not require credentials when the calling application exposes the parser to remote users. Post-exploitation actions include credential theft, lateral movement, deployment of remote access tooling, and manipulation of AI agent outputs.
No verified proof-of-concept code is available. See the GitHub advisory for MetaGPT command injection for technical details.
Detection Methods for CVE-2026-79408
Indicators of Compromise
- Unexpected child processes spawned by the Python interpreter hosting MetaGPT, such as /bin/sh, bash, curl, wget, or nc
- Shell metacharacters (;, |, &&, backticks, $()) appearing in path parameters logged by MetaGPT or upstream applications
- Outbound connections from MetaGPT hosts to unfamiliar domains shortly after repository parsing operations
Detection Strategies
- Instrument MetaGPT to log every invocation of RepoParser.rebuild_class_views() with the raw path argument and correlate against a shell-metacharacter allow-list
- Deploy endpoint behavioral rules that alert when the Python process running MetaGPT spawns interactive shells or common post-exploitation binaries
- Apply web application firewall (WAF) signatures to API endpoints that forward user input into MetaGPT parser routines
Monitoring Recommendations
- Forward MetaGPT application logs and process telemetry into a centralized SIEM for correlation with network egress events
- Monitor for CWE-78 patterns across all AI agent frameworks, not only MetaGPT, because similar sinks exist in adjacent tooling
- Track file-system writes under MetaGPT working directories for dropped scripts or staged payloads
How to Mitigate CVE-2026-79408
Immediate Actions Required
- Identify all deployments running MetaGPT 0.8.1 and restrict network access to trusted operators only
- Remove or disable code paths that expose RepoParser.rebuild_class_views() to unauthenticated or untrusted callers
- Run MetaGPT under a dedicated low-privilege service account inside a container with no outbound internet access by default
Patch Information
At the time of publication, no fixed release is referenced in the NVD entry for CVE-2026-79408. Monitor the MetaGPT command injection advisory and the upstream MetaGPT project for a patched version. Apply the update as soon as a fixed release becomes available.
Workarounds
- Wrap RepoParser.rebuild_class_views() callers with strict input validation that rejects any path value containing shell metacharacters or non-filesystem characters
- Replace shell-based invocations with subprocess.run([...], shell=False) and pass arguments as a list to eliminate shell interpretation
- Enforce a Linux seccomp or AppArmor profile that blocks execve of shell interpreters from the MetaGPT Python process
# Configuration example: run MetaGPT with a restricted systemd unit
[Service]
User=metagpt
Group=metagpt
NoNewPrivileges=true
ProtectSystem=strict
ProtectHome=true
PrivateTmp=true
RestrictSUIDSGID=true
SystemCallFilter=~@debug @mount @privileged @reboot @swap @raw-io
CapabilityBoundingSet=
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
