GHSA-xcx6-vp38-8hr5

## Summary The `object.to_json` builtin function in Scriban performs recursive JSON serialization via an internal `WriteValue()` static local function that has no depth limit, no circular reference detection, and no stack overflow guard. A Scriban template containing a self-referencing object passed to `object.to_json` triggers unbounded recursion, causing a `StackOverflowException` that terminates the hosting .NET process. This is a fatal, unrecoverable crash — `StackOverflowException` cannot be caught by user code in .NET. ## Details The vulnerable code is the `WriteValue()` static local function at `src/Scriban/Functions/ObjectFunctions.cs:494`: ```csharp static void WriteValue(TemplateContext context, Utf8JsonWriter writer, object value) { var type = value?.GetType() ?? typeof(object); if (value is null || value is string || value is bool || type.IsPrimitiveOrDecimal() || value is IFormattable) { JsonSerializer.Serialize(writer, value, type); } else if (value is IList || type.IsArray) { writer.WriteStartArray(); foreach (var x in context.ToList(context.CurrentSpan, value)) { WriteValue(context, writer, x); // recursive, no depth check } writer.WriteEndArray(); } else { writer.WriteStartObject(); var accessor = context.GetMemberAccessor(value); foreach (var member in accessor.GetMembers(context, context.CurrentSpan, value)) { if (accessor.TryGetValue(context, context.CurrentSpan, value, member, out var memberValue)) { writer.WritePropertyName(member); WriteValue(context, writer, memberValue); // recursive, no depth check } } writer.WriteEndObject(); } } ``` This function has **none** of the safety mechanisms present in other recursive paths: - `ObjectToString()` at `TemplateContext.Helpers.cs:98` checks `ObjectRecursionLimit` (default 20) - `E