Command Injection in Picobot Agent Tool

Executive Summary

CVE-2026-15669 is an OS command injection vulnerability in the louisho5 picobot software, specifically affecting versions up to 0.2.0. The issue resides in the ExecTool.Execute function within the file internal/agent/tools/exec.go.

The vulnerability occurs because the exec tool in Picobot is designed to restrict dangerous programs by checking only the first token (argv[0]) of a command array against a blacklist. However, it fails to inspect nested shell payloads or subsequent tokens in the command array. This allows attackers to bypass restrictions by using shell wrappers like sh -c or /usr/bin/env bash -lc with malicious commands.

For example, commands such as ["sh", "-c", "echo malicious-command > file.txt"] or ["/usr/bin/env", "bash", "-lc", "rm -rf /"] would bypass the blacklist because the tool only checks the first token (sh or /usr/bin/env) and not the rest of the command. This results in arbitrary command execution under the Picobot OS user.

The vulnerability is classified as CWE-78 (OS Command Injection) and has been publicly disclosed with a proof-of-concept demonstrating the bypass.

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Detection Guidance

To detect the vulnerability CVE-2026-15669 on your system, you can check if the affected Picobot version (<= 0.2.0) is running and inspect its behavior for signs of exploitation or misconfiguration.

• Check the installed version of Picobot. If it is version 0.2.0 or earlier, it is vulnerable. You can verify the version by running the Picobot binary with the --version flag, if supported, or inspect the binary metadata.
• Look for unexpected files or modifications in the Picobot process directory. The vulnerability allows arbitrary command execution, which could create or modify files. For example, search for files like 'marker.txt' or other unexpected artifacts in the working directory of the Picobot process.
• Monitor process execution logs for suspicious commands, particularly those involving shell wrappers like 'sh -c', '/usr/bin/env bash -lc', or other nested command structures. Tools like 'auditd' or 'sysdig' can help track process execution.
• Review the Picobot configuration and logs for evidence of the 'exec' tool being used with array-form commands (e.g., ['sh', '-c', '<payload>']). Logs may reveal attempts to bypass the blacklist by wrapping dangerous commands.
• Test for the vulnerability by attempting to execute a benign command via the 'exec' tool using a shell wrapper. For example, try running a command like ['sh', '-c', 'echo test > detection_test.txt'] through the Picobot agent. If the file 'detection_test.txt' is created, the system is vulnerable.

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Impact Analysis

This vulnerability can have several impacts if you are using Picobot versions up to 0.2.0:

• Arbitrary command execution: An attacker can execute any command on the system where Picobot is running, potentially gaining control over the host.
• Data exposure: Sensitive data accessible to the Picobot process or user could be read, exfiltrated, or manipulated.
• Tampering with local resources: Attackers could modify or delete files, disrupt services, or install malicious software on the system.
• Privilege escalation: If Picobot is running with elevated privileges, the attacker could escalate their access to higher levels of system control.

The impact is particularly severe if Picobot is integrated with platforms like Telegram, Discord, Slack, or WhatsApp, as an attacker could exploit the vulnerability through these channels to execute commands remotely.

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Compliance Impact

This vulnerability can affect compliance with several common standards and regulations in the following ways:

• GDPR (General Data Protection Regulation): If Picobot processes or stores personal data of EU citizens, this vulnerability could lead to unauthorized access or exfiltration of that data. Under GDPR, organizations must implement appropriate technical measures to protect personal data. A breach resulting from this vulnerability could lead to significant fines and legal consequences.
• HIPAA (Health Insurance Portability and Accountability Act): If Picobot is used in a healthcare environment to handle protected health information (PHI), this vulnerability could result in unauthorized access to PHI. HIPAA requires safeguards to ensure the confidentiality, integrity, and availability of PHI. A breach could lead to violations, penalties, and loss of trust.
• PCI DSS (Payment Card Industry Data Security Standard): If Picobot is involved in processing, transmitting, or storing payment card data, this vulnerability could expose cardholder data. PCI DSS requires strict controls to protect such data, and a breach could result in non-compliance and financial penalties.
• ISO 27001: This standard requires organizations to manage information security risks. The presence of an unpatched OS command injection vulnerability would likely be considered a significant risk, potentially leading to non-compliance with ISO 27001 controls related to secure coding, vulnerability management, and access control.

In summary, this vulnerability undermines the security controls required by these regulations and standards, potentially leading to non-compliance, legal repercussions, and reputational damage.

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Mitigation Strategies

To mitigate the vulnerability CVE-2026-15669, follow these immediate steps to reduce the risk of exploitation.

• Upgrade Picobot to a patched version as soon as one is available. Since the project has not yet responded to the issue, monitor the official repository or issue tracker for updates and apply them promptly.
• If upgrading is not immediately possible, disable or remove the 'exec' tool from the Picobot configuration. This prevents the vulnerable component from being used until a fix is applied.
• Restrict access to the Picobot agent to trusted users only. Since the vulnerability requires local access, limiting who can interact with the agent reduces the attack surface.
• Implement additional monitoring and logging for the Picobot process. Track all commands executed by the 'exec' tool and set up alerts for suspicious activity, such as shell wrapper usage or blacklisted commands.
• Apply least-privilege principles to the Picobot process. Run the agent with the minimum necessary permissions to limit the impact of any potential exploitation. Avoid running it as a privileged user (e.g., root).
• Consider using additional security tools, such as AppArmor, SELinux, or seccomp, to restrict the actions the Picobot process can perform. This can help contain any potential exploitation attempts.
• Review and harden the system where Picobot is running. Ensure that sensitive files and directories are protected with appropriate permissions and that the system is up to date with security patches.

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