8.1High
CVE-2026-85660
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.
What this means for your business
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.5% chance of attack attempts being seen in the next 30 days, ranking above 39% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
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Scoring
- CVSS
- 8.1 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H- CVSS v4
- 9.2
- Weakness
- CWE-78
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-09-04
- Last modified
- 2026-09-04
- Sources
- NVD
References
- https://github.com/MladenSU/cli-mcp-server
- https://github.com/MladenSU/cli-mcp-server/blob/main/src/cli_mcp_server/server.py
- https://github.com/MladenSU/cli-mcp-server/issues/17
- https://www.vulncheck.com/advisories/cli-mcp-server-0.2.5-command-allowlist-bypass-via-shell-substitution
- https://github.com/MladenSU/cli-mcp-server/issues/17