CVE-2026-81096
ToolUniverse through 1.2.6 Unauthenticated Remote Code Execution via python_code_executor Sandbox Escape
- State
- Published
- Severity
- 9.3 Critical
- Published
- Aug 27, 2026
- Updated
- Aug 29, 2026
- Reserved
- Aug 26, 2026
Description
ToolUniverse ran caller-supplied Python inside a sandbox that could be escaped, on a server that required no authentication. The executor behind the python_code_executor tool, in python_executor_tool.py, inspected the submitted source for a denied list of attribute names and calls but left the attribute-lookup builtins available and did not stop a dunder attribute reached through a string lookup or through a module already permitted, so a caller could walk from a literal's class to its base and enumerate subclasses to obtain a reference to the process and subprocess modules. A per-call argument also let the caller widen the import allow-list before the inspection ran. The HTTP and MCP servers in http_api_server.py and smcp_server.py bound to every interface with debugging enabled and no authentication, so any caller able to reach the port executed code as the server process. Version 1.3.0 adds bearer-token authentication, defaults the bind address to loopback, and hardens the attribute checks.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 9.3 Critical | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 10.0 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H | VulnCheck |
Weaknesses
- CWE-94 Improper Control of Generation of Code ('Code Injection')
Affected Products
| Product | Versions |
|---|---|
ToolUniversemims-harvard |
|
References
- https://github.com/mims-harvard/ToolUniverseproduct
- https://github.com/mims-harvard/ToolUniverse/pull/251issue-trackingpatch
- GitHub Security Advisory (GHSA-pxwq-22vf-87fm)vendor-advisory
- VulnCheck Advisory: ToolUniverse through 1.2.6 Unauthenticated Remote Code Execution via python_code_executor Sandbox Escapethird-party-advisory
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