Disclosed vulnerability
CVE-2026-81096: ToolUniverse Python sandbox escape plus unauthenticated MCP/HTTP servers bound to all interfaces
AIR-2026-0206 AIR record · 2026-08-tooluniverse-sandbox-escape-unauth-rce
From the supporting source
walk from a literal's class to its base and enumerate subclasses to obtain a reference to the process and subprocess modules.github.com
The record
Disclosed
2026-08-27
Vendor
ToolUniverse maintainers
Product
ToolUniverse
Risk domain
Access control and permissions › Privilege escalation
System type
Generative model
Who acted
AI was the target — a Python sandbox escape on unauthenticated MCP/HTTP servers
Attack surface
MCP server
Autonomy level
Semi-autonomous
Initial vector
Caller supplied python to an unauthenticated endpoint
Impact type
Sandbox escape, Remote code execution
Confidence
High
Submitted by
EAI Internal
Crosswalk
- OWASP Agentic Top 10 (2026)
- ASI03 – Identity and Privilege Abuse
- MITRE ATLAS
- AML.T0055 – Unsecured Credentials
- NIST AI RMF
- GOVERN 6.1
- EU AI Act
- Article 13
- ISO/IEC
- TR 24028; 42001; 23894
- AIUC-1
- B. Security
- Scope
- tool misuse
- Mitigation
- Apply least-privilege principle; Regular policy audits.
- Taxonomy
- Enkrypt AI agent risk taxonomy · Black-Box Red Teaming of Agentic AI: A Taxonomy-Driven Framework for Automated Risk Discovery
Blast radius
ToolUniverse through 1.2.6, exposed on every interface with debugging on and no auth
Capability abused
Defense & remediation
Recorded defense
a Python code-execution sandbox that still exposed attribute-lookup builtins
Guardrail kinds
Sandbox isolation
Guardrail outcome
Silent
Fix shipped
ToolUniverse 1.3.0 - bearer-token auth, loopback-only bind, stricter attribute validation
Taxonomy & references
Curator notes
GHSA-rg68-wg77-c3wm, CVSS 9.3 Critical, published 2026-08-27. The classic Python subclass-walk sandbox escape, still shipping inside agent tool servers in 2026. Included as a representative of the 'MCP tool server with no auth plus a homemade Python sandbox' pattern seen repeatedly in the August 2026 batch of unreviewed MCP advisories.
Supporting sources
Cite as
Enkrypt AI. "CVE-2026-81096: ToolUniverse Python sandbox escape plus unauthenticated MCP/HTTP servers bound to all interfaces". AIR, AIR-2026-0206. https://agentincident.vercel.app/i/AIR-2026-0206/ (accessed 2026-10-19).