Security Policy

Reporting a vulnerability

Please report security vulnerabilities privately by opening a GitHub Security Advisory for this repository (preferred) or by contacting the maintainer directly.

Do not disclose vulnerabilities publicly before a fix is available and maintainers have completed triage.

Execution trust model

This repository includes runtime execution facilities (Wistc run, REPL, and programmatic execution hosts).

Dialect examples can constrain composition (for example, arithmetic-only interpreter profiles), but those constraints must not be interpreted as fully hardened sandbox guarantees unless explicit code-level isolation controls are added and verified.

Treat untrusted script execution as high risk. If you must run untrusted input, isolate it at the process/environment level and disable unsafe capabilities by composition.

Internal targeted runtime activation (exact loading of selected component/registrar types) is an implementation detail, not a sandbox boundary. Constrained dialect composition is still not equivalent to hardened sandboxing. Do not treat "exact activation" as a security guarantee for untrusted code execution.

Supported versions

This repository is currently developed on the default development branch and targets .NET 10 (net10.0). Security fixes are expected to be applied there.

Alpha host controls

The public facade now applies two bounded controls before composition or execution:

• WistEngineOptions.AllowedAssemblies is the explicit host CLR type/method allowlist. Only the shipped BasicStdLib assembly is added by the runtime; selected dialect implementation assemblies are not exposed. Runtime discovery does not inspect AppDomain.CurrentDomain, AppContext.BaseDirectory, or recursively load DLLs from disk.
• WistEngineOptions.ResourceLimits limits UTF-16 source length and external parameter count. Limit failures use stable structured diagnostic codes (UTC-WIST-001 and UTC-WIST-002).

These are defense-in-depth and denial-of-service preflight checks, not a sandbox. They do not interrupt a long-running compiled delegate, constrain heap allocation, isolate native calls, or revoke capabilities after a host deliberately adds an assembly. For arbitrary untrusted authors, execute in a separate constrained process/container and enforce wall-clock, CPU, memory, filesystem, network, and identity limits outside Wist.

The name CreateRestrictedArithmetic describes the actual guarantee. Ambiguous “safe” or “trusted” aliases are intentionally not part of the public API because they could be misread as process-isolation guarantees.