CVE-2026-0758: Siri Shortcuts Privilege Escalation Flaw

CVE-2026-0758 Overview

CVE-2026-0758 is a command injection vulnerability affecting mcp-server-siri-shortcuts that allows local attackers to escalate privileges on affected installations. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the shortcutName parameter. The issue results from the lack of proper validation of a user-supplied string before using it to execute a system call. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of the service account. This vulnerability was tracked as ZDI-CAN-27910.

Critical Impact

Successful exploitation allows privilege escalation and arbitrary code execution in the context of the service account, potentially compromising the entire system.

Affected Products

• mcp-server-siri-shortcuts (all versions prior to patch)

Discovery Timeline

• 2026-01-23 - CVE-2026-0758 published to NVD
• 2026-01-26 - Last updated in NVD database

Technical Details for CVE-2026-0758

Vulnerability Analysis

This vulnerability is classified as CWE-78 (Improper Neutralization of Special Elements used in an OS Command), commonly known as OS Command Injection. The flaw allows an attacker with local access to inject malicious commands through the shortcutName parameter, which is then passed unsanitized to a system call. This represents a classic command injection pattern where user-controlled input flows directly into command execution without proper sanitization or parameterization.

The attack requires local access and low-privilege code execution as a prerequisite, making this a local privilege escalation vector rather than a remote attack. Once exploited, the attacker gains the ability to execute arbitrary commands with the privileges of the service account running mcp-server-siri-shortcuts.

Root Cause

The root cause is insufficient input validation on the shortcutName parameter. The application fails to properly sanitize or validate user-supplied input before incorporating it into system command execution. This allows shell metacharacters and command separators to be interpreted by the underlying shell, enabling command injection.

Attack Vector

The attack requires local access to a system running mcp-server-siri-shortcuts. An attacker with low-privileged code execution capabilities can craft a malicious shortcutName value containing shell metacharacters (such as ;, |, &&, or backticks) to inject additional commands. When the application processes this input and passes it to a system call, the injected commands execute with the elevated privileges of the service account.

For example, a crafted shortcut name containing command separators would allow appending arbitrary commands to be executed alongside the intended operation. The lack of input sanitization means the application treats the entire string, including injected commands, as legitimate input for the system call.

For detailed technical information about this vulnerability, refer to the Zero Day Initiative Advisory ZDI-26-024.

Detection Methods for CVE-2026-0758

Indicators of Compromise

• Unexpected child processes spawned by the mcp-server-siri-shortcuts service
• Unusual command-line arguments containing shell metacharacters in shortcut operations
• Evidence of privilege escalation attempts in system logs related to the service account

Detection Strategies

• Monitor system call activity from the mcp-server-siri-shortcuts process for suspicious command execution patterns
• Implement endpoint detection rules to alert on shell metacharacters in shortcut name parameters
• Review audit logs for unexpected execution of system commands by the service account
• Deploy behavioral analysis to detect anomalous process trees originating from the service

Monitoring Recommendations

• Enable verbose logging for mcp-server-siri-shortcuts service operations
• Configure SIEM alerts for command injection patterns in application logs
• Monitor for creation of new files or processes by the service account outside normal operational scope
• Implement file integrity monitoring on critical system files accessible to the service account

How to Mitigate CVE-2026-0758

Immediate Actions Required

• Review and restrict access to systems running mcp-server-siri-shortcuts to trusted users only
• Implement application-level input validation to reject shortcut names containing shell metacharacters
• Consider running the service with minimal required privileges following the principle of least privilege
• Monitor for any signs of exploitation using the detection strategies outlined above

Patch Information

Consult the Zero Day Initiative Advisory ZDI-26-024 for the latest patch information and vendor response. Apply any available security updates from the mcp-server-siri-shortcuts maintainers as soon as they become available.

Workarounds

• Implement strict input validation on the shortcutName parameter to allow only alphanumeric characters and safe special characters
• Use allowlist-based filtering to restrict shortcut names to known safe patterns
• Run the mcp-server-siri-shortcuts service in a sandboxed environment to limit the impact of successful exploitation
• Consider disabling the affected functionality until a patch is available if the service is not critical

# Example: Restricting service account privileges
# Ensure the service runs with minimal required permissions
chmod 700 /path/to/mcp-server-siri-shortcuts
chown service_account:service_group /path/to/mcp-server-siri-shortcuts

# Implement filesystem restrictions to limit potential damage
# Configure AppArmor or SELinux policies to restrict process capabilities