---
title: "GHSA-w28w-gp39-m4p6: Prompty: Server-Side Template Injection to Remote Code Execution in the @prompty/core Nunjucks Renderer"
url: https://erroneo.us/security/ghsa/GHSA-w28w-gp39-m4p6/
description: "GHSA-w28w-gp39-m4p6 (critical, npm): Prompty: Server-Side Template Injection to Remote Code Execution in the @prompty/core Nunjucks Renderer. Summary The…"
type: advisory
section: "Security Digest"
date_published: 2026-07-24
date_modified: 2026-07-24
publisher: erroneo.us
author: erroneo.us Security Desk
ghsa: "GHSA-w28w-gp39-m4p6"
license: All rights reserved. Quote with attribution and a link.
---

# GHSA-w28w-gp39-m4p6: Prompty: Server-Side Template Injection to Remote Code Execution in the @prompty/core Nunjucks Renderer

## Affected packages

- npm `@prompty/core` <= 0.1.4 → fixed: 0.1.5
- npm `@prompty/core` >= 2.0.0-alpha.1, <= 2.0.0-beta.4 → fixed: 2.0.0-beta.5

## Details

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

## Sources

- [GitHub Advisory GHSA-w28w-gp39-m4p6](https://github.com/advisories/GHSA-w28w-gp39-m4p6)
- [github.com](https://github.com/microsoft/prompty/security/advisories/GHSA-w28w-gp39-m4p6)
- [github.com](https://github.com/microsoft/prompty/pull/404)
- [github.com](https://github.com/microsoft/prompty/commit/047756f4c8caf91c5868eeb42520c938393277b0)

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Source page: https://erroneo.us/security/ghsa/GHSA-w28w-gp39-m4p6/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt