CVE•Published 2026-08-25•Modified 2026-09-09•1 article on news•5 live references•NVD data

CVE-2026-55581

Vulnerability data via NVD (ingested)

CVSS v3.1

8.4

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS percentile

Exploit Prediction Scoring System · top 73% of all CVEs

Weaknesses (CWE)

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')CWE-183Permissive List of Allowed Inputs CWE-1188Initialization of a Resource with an Insecure Default

Description

mcp-shell is an MCP server for running shell commands securely, auditably, and on demand. Prior to 0.6.0, the default Docker security.yaml includes /bin/bash in allowed_executables, while security.go validates only the first token and checkBlockedPatternsAndCommands does not reject the shell command-mode flag -c. A caller of the shell_exec MCP tool can provide the command argument `/bin/bash -c <arbitrary-command>`, which passes validation and reaches executor.go, where parseCommand and exec.CommandContext execute the arbitrary command as mcpuser outside the intended allowlist. This issue is fixed in version 0.6.0.

Timeline

Published 2026-08-25

Modified 2026-09-09

External references

NVD MITRE Exploit-DB trickest/cve VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-55581

Hosts Shodan has explicitly fingerprinted as vulnerable.

More intel sources (5)

Shodan report

vuln:CVE-2026-55581

Country / ASN / product breakdown for the vuln query.

Censys

vulnerabilities.cve_id: CVE-2026-55581

Censys host search filtered to this CVE id.

grep.app

CVE-2026-55581