CVE-2026-81097: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in maquina-app rails-mcp-server
The execute_ruby tool is documented as a read-only Ruby sandbox and is enforced by a pattern denylist together with replacements for the process-spawning methods on Kernel. The pseudo-terminal library's spawn entry points are neither in the denylist nor replaced, so a normal tool call could reach them and start a shell, executing commands as the account running the server and outside the guarded methods. The denylist was introduced with the tool in 1.4.0 and never covered those entry points through 1.6.0. Version 1.6.1 restricts the requires the sandbox permits to a data-only list and blocks dynamic dispatch to execution entry points; 2.0.0 removes the tool.
CVE-2026-81097: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in maquina-app rails-mcp-server
Description
The execute_ruby tool is documented as a read-only Ruby sandbox and is enforced by a pattern denylist together with replacements for the process-spawning methods on Kernel. The pseudo-terminal library's spawn entry points are neither in the denylist nor replaced, so a normal tool call could reach them and start a shell, executing commands as the account running the server and outside the guarded methods. The denylist was introduced with the tool in 1.4.0 and never covered those entry points through 1.6.0. Version 1.6.1 restricts the requires the sandbox permits to a data-only list and blocks dynamic dispatch to execution entry points; 2.0.0 removes the tool.
CVSS v4.0
Score 8.6high
Affected software
pkg:github/rails-mcp-serverRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-26T16:00:32.686Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a906bafacd9273b4983a0f1
Added to database: 08/27/2026, 16:54:07 UTC
Last updated: 08/28/2026, 02:59:22 UTC
Views: 9
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