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CVE PROGRAM SOURCE RECORD10.0 Critical

CVE-2026-73299

Prompty: Server-Side Template Injection to Remote Code Execution in the @prompty/core Nunjucks Renderer

Description

Prompty is a markdown file format (.prompty) for LLM prompts. Prior to 0.1.5 and 2.0.0-beta.5, 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. This issue is fixed in versions 0.1.5 and 2.0.0-beta.5.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

microsoft prompty

  • < 0.1.5affected
  • >= 2.0.0-alpha.1, < 2.0.0-beta.5affected

References