CVE-2026-6117: AstrBot RCE Vulnerability via Upload

CVE-2026-6117 Overview

A sandbox bypass vulnerability has been discovered in AstrBotDevs AstrBot up to version 4.22.1. This security flaw exists in the install_plugin_upload function within the file astrbot/dashboard/routes/plugin.py, which is part of the install-upload endpoint. By manipulating the File argument, an attacker can bypass sandbox restrictions, potentially leading to unauthorized code execution or access to protected system resources.

Critical Impact

Remote attackers with low privileges can exploit this sandbox bypass vulnerability to escape intended security boundaries, potentially gaining unauthorized access to system resources or executing arbitrary operations outside the sandboxed environment.

Affected Products

• AstrBot versions up to and including 4.22.1
• AstrBot Dashboard Plugin Management Component
• AstrBot install-upload Endpoint (astrbot/dashboard/routes/plugin.py)

Discovery Timeline

• 2026-04-12 - CVE-2026-6117 published to NVD
• 2026-04-13 - Last updated in NVD database

Technical Details for CVE-2026-6117

Vulnerability Analysis

This vulnerability is classified under CWE-264 (Permissions, Privileges, and Access Controls), indicating a fundamental flaw in how the application enforces security boundaries. The install_plugin_upload function fails to properly validate and sanitize uploaded files, allowing attackers to craft malicious payloads that escape the intended sandbox environment.

The sandbox bypass occurs when the application processes plugin uploads through the dashboard interface. The vulnerable endpoint does not adequately restrict what operations uploaded plugins can perform, effectively nullifying the protective sandbox meant to isolate plugin code from sensitive system resources.

The network-accessible nature of this vulnerability means that any authenticated user with access to the plugin upload functionality can potentially exploit this flaw. The exploit has been publicly disclosed and documented in GitHub Issue #7168.

Root Cause

The root cause of this vulnerability lies in insufficient input validation and improper access control implementation within the install_plugin_upload function. The File argument handling does not enforce adequate restrictions on the content or behavior of uploaded plugins, allowing malicious code to break out of the sandbox environment.

The permissions and privilege enforcement mechanism fails to properly isolate uploaded plugin code, enabling attackers to access resources that should be protected by the sandbox boundary.

Attack Vector

The attack is executed remotely via the network by an authenticated attacker with low-level privileges. The exploitation process involves:

1. An attacker authenticates to the AstrBot dashboard with minimal privileges
2. The attacker navigates to the plugin upload functionality at the install-upload endpoint
3. A specially crafted malicious file is uploaded that exploits the sandbox bypass
4. The vulnerable install_plugin_upload function processes the file without proper sandbox enforcement
5. The malicious payload escapes the sandbox, gaining access to protected system resources

The vulnerability requires no user interaction beyond the attacker's own actions, making it straightforward to exploit once the attacker has basic authentication credentials.

Detection Methods for CVE-2026-6117

Indicators of Compromise

• Unusual file uploads to the plugin installation endpoint with suspicious or obfuscated content
• Plugin execution logs showing access attempts to system resources outside the expected sandbox boundaries
• Unexpected network connections or file system access originating from the AstrBot application context
• Authentication logs showing repeated access to the install-upload endpoint from unusual sources

Detection Strategies

• Monitor HTTP requests to the /install-upload endpoint for suspicious file upload patterns or unusual payload sizes
• Implement file content inspection for uploaded plugins to detect potential sandbox escape payloads
• Configure logging to capture all plugin installation attempts with full request details for forensic analysis
• Deploy application-level monitoring to detect unauthorized resource access from the AstrBot process

Monitoring Recommendations

• Enable verbose logging for the AstrBot dashboard, particularly for plugin management operations
• Set up alerts for any plugin installation activity from untrusted or unexpected user accounts
• Monitor system call activity from the AstrBot process for indicators of sandbox escape attempts
• Review access logs regularly for patterns indicating exploitation attempts against the plugin upload functionality

How to Mitigate CVE-2026-6117

Immediate Actions Required

• Restrict access to the plugin upload functionality to only highly trusted administrators
• Implement additional network-level controls to limit access to the AstrBot dashboard from trusted IP ranges only
• Consider disabling the plugin upload feature entirely if not required for operations
• Audit existing installed plugins for any signs of malicious activity or unauthorized modifications

Patch Information

As of the last update, the AstrBot project has been notified of this vulnerability through GitHub Issue #7168 but has not yet responded with an official patch. Users should monitor the AstrBot GitHub repository for security updates and upgrade to a patched version as soon as one becomes available.

Additional technical details about this vulnerability can be found in VulDB #356977.

Workarounds

• Implement a web application firewall (WAF) rule to inspect and potentially block suspicious uploads to the install-upload endpoint
• Deploy the AstrBot application within a containerized environment with strict resource isolation to limit the impact of sandbox escapes
• Configure file upload validation at the reverse proxy level to reject potentially malicious file types or content patterns
• Implement multi-factor authentication for dashboard access to reduce the risk of unauthorized plugin uploads

# Example: Restrict access to AstrBot dashboard using iptables
# Allow only trusted IP addresses to access the dashboard port
iptables -A INPUT -p tcp --dport 8080 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP

# Example: Run AstrBot in a restricted container with limited capabilities
# docker run --cap-drop=ALL --security-opt=no-new-privileges astrbot:latest