Vulnerability · Published Sep 4, 2026 · Assigned by VulnCheck
CVE-2026-85660cli-mcp-server 0.2.5 Command Allowlist Bypass via Shell Substitution
High 8.1
In plain English
A high-severity OS command injection in cli-mcp-server from MladenSU. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities).
Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.6%top 50.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
cli-mcp-server 0.2.5 contains a command allowlist bypass vulnerability in the _validate_command_with_operators function when ALLOW_SHELL_OPERATORS is enabled. Attackers can use shell command substitution syntax like $(...) or backticks to execute non-allowlisted commands that bypass the ALLOWED_COMMANDS validation check.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| MladenSU | cli-mcp-server | 0 – through 0.2.5 |
Weakness: CWE-78 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- GitHub Issue #17 issue-tracking
- https://github.com/MladenSU/cli-mcp-server product
- https://github.com/MladenSU/cli-mcp-server/blob/main/src/cli_mcp_server/server.py technical-description
- VulnCheck Advisory: cli-mcp-server 0.2.5 Command Allowlist Bypass via Shell Substitution third-party-advisory