CVE-2026-55582: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in sonirico mcp-shell
Description
CVE-2026-55582 is an OS command injection vulnerability in sonirico mcp-shell prior to version 0.6.0. The default security configuration allows the use of /usr/bin/git without proper argument restrictions, enabling an attacker to inject arbitrary OS commands via Git aliases. This vulnerability can be exploited by any user with MCP connectivity, as the default Docker image runs as mcpuser with Git installed and secure mode enabled. The issue is fixed in version 0.6.0.
CVSS v3.1
Score 8.4high
Affected software
sonirico
mcp-shell
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability arises because mcp-shell's default security.yaml permits /usr/bin/git, and the security.go code fails to properly neutralize shell metacharacters or enforce per-executable argument policies. An attacker can supply a crafted command argument to the shell_exec MCP tool, such as '/usr/bin/git -c alias.pwn=!<arbitrary-command>', causing Git to create a shell alias that executes arbitrary OS commands with the privileges of the mcp-shell process user. This flaw is exploitable in the default deployment without additional authentication beyond MCP connectivity. The vulnerability is resolved in mcp-shell version 0.6.0.
Potential Impact
Successful exploitation allows an attacker with MCP connectivity to execute arbitrary OS commands as the mcp-shell process user (mcpuser by default in Docker). This leads to full confidentiality, integrity, and availability compromise of the affected system under the mcpuser context.
Mitigation Recommendations
Upgrade to mcp-shell version 0.6.0 or later, where this vulnerability is fixed. Until then, restrict MCP connectivity to trusted users only. No official patch link is provided, but the vendor states the issue is fixed in version 0.6.0.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-16T23:18:03.169Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a8dba54acd9273b4965b604
Added to database: 08/25/2026, 15:52:52 UTC
Last enriched: 09/10/2026, 04:22:32 UTC
Last updated: 10/07/2026, 18:48:21 UTC
Views: 35
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