Answer in brief
CVE-2026-55580 records a High severity (CVSS 0.0) vulnerability in mcp-shell — Security Disabled by Default in Bare-Binary Deploy Path + Shell Interpreter in Secure-Mode Allowlist. The current sources do not mark it as known exploited. The current feed maps sonirico/mcp-shell (generic), github.com/sonirico/mcp-shell (go), github.com/sonirico/mcp-shell (go). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 0.0. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps sonirico/mcp-shell (generic), github.com/sonirico/mcp-shell (go), github.com/sonirico/mcp-shell (go). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| sonirico/mcp-shellgeneric | < 0.6.0 | Not reported |
| github.com/sonirico/mcp-shellgo | <0.6.0 | 0.6.0 |
| github.com/sonirico/mcp-shellgo | >=0 <0.6.0 | 0.6.0 |
Published upstream
Aug 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 25, 2026
mcp-shell is an MCP server for running shell commands securely, auditably, and on demand. Prior to 0.6.0, config.go initializes Security.Enabled to false, and when MCP_SHELL_SEC_CONFIG_FILE is unset, main.go starts the documented bare-binary deployment without a security policy. SecurityValidator.validateCommand in security.go then short-circuits and allows every command supplied to the shell_exec MCP tool, so an LLM connected over stdio can execute unrestricted OS commands as the mcp-shell process user. The README from-source installation and MCP client configuration omit MCP_SHELL_SEC_CONFIG_FILE, making the insecure state the documented default. This issue is fixed in version 0.6.0.
Quoted source text, attributed separately from HOL analysis.