CVE-2026-85660 Details
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.
A command allowlist bypass vulnerability has been identified in cli-mcp-server version 0.2.5. This issue arises in the _validate_command_with_operators function when the ALLOW_SHELL_OPERATORS option is enabled. The vulnerability allows attackers to exploit shell command substitution syntax, such as $(...) or backticks, to execute commands that are not included in the allowlist, thereby circumventing the ALLOWED_COMMANDS validation.
Users are advised to disable the ALLOW_SHELL_OPERATORS option or to implement a more robust validation mechanism that rejects command substitution and backticks before execution. Alternatively, commands can be parsed into arguments and executed without a shell, ensuring that only allowlisted commands are run.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Sep 4, 2026CISA-ADP
Assessed Sep 4, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/MladenSU/cli-mcp-server/issues/17 | CISA-ADP | ExploitIssue TrackingTechnical DescriptionVendor |
| https://github.com/MladenSU/cli-mcp-server | [email protected] | Source CodeVendor |
| https://github.com/MladenSU/cli-mcp-server/blob/main/src/cli_mcp_server/server.py | [email protected] | Source CodeVendor |
| https://github.com/MladenSU/cli-mcp-server/issues/17 | [email protected] | ExploitIssue TrackingTechnical DescriptionVendor |
| https://www.vulncheck.com/advisories/cli-mcp-server-0.2.5-command-allowlist-bypass-via-shell-substitution | [email protected] | Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-78 | Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| MladenSU cli-mcp-server | <= 0.2.5 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 4, 2026 | CVE Modified | CISA-ADP |
| Sep 4, 2026 | New CVE Received | [email protected] |