CVE-2026-73299

## Summary The TypeScript Nunjucks renderer evaluated untrusted `.prompty` template bodies with unrestricted JavaScript member access. An attacker-controlled template could traverse constructor and prototype properties to execute JavaScript in the host Node.js process. ## Affected packages - npm `@prompty/core` versions `<= 0.1.4` - npm `@prompty/core` versions `<= 2.0.0-beta.4` ## Impact Applications that render untrusted, community-supplied, cloned, or LLM-generated `.prompty` files with the TypeScript runtime could allow attacker-controlled code execution with the privileges of the Node.js host process. ## Remediation Upgrade to `@prompty/core` `2.0.0-beta.5` or later. The patched renderer sanitizes render inputs to own-data-only values, rejects constructor/prototype member traversal, and disallows template function calls. Ordinary interpolation, conditionals, loops, and own nested data properties remain supported. ## Fix details The fix is merged in PR #404 and includes regression coverage for default Nunjucks rendering, explicit renderer usage, unsafe member lookups, and attempted template function calls.

Prompty es un formato de archivo markdown (.prompty) para prompts de LLM. Antes de las versiones 0.1.5 y 2.0.0-beta.5, el renderizador TypeScript Nunjucks evaluaba cuerpos de plantillas .prompty no confiables con acceso irrestricto a miembros de JavaScript. Una plantilla controlada por el atacante podría recorrer propiedades de constructor y prototipo para ejecutar JavaScript en el proceso host de Node.js. Este problema está solucionado en las versiones 0.1.5 y 2.0.0-beta.5.