CriticalVulnerability
GHSA-w28w-gp39-m4p6: Prompty: Server-Side Template Injection to Remote Code Execution in the @prompty/core Nunjucks Renderer
- Identifier
- GHSA-w28w-gp39-m4p6
- Published
- Record updated
- Affected
- @prompty/core >= 2.0.0-alpha.1, <= 2.0.0-beta.4, fixed in 2.0.0-beta.5, released July 20, 2026, 4 days before disclosure
- @prompty/core <= 0.1.4, fixed in 0.1.5, released July 20, 2026, 4 days before disclosure
Summary
The TypeScript Nunjucks renderer in @prompty/core evaluated untrusted .prompty template bodies with unrestricted JavaScript member access. An attacker-controlled template could traverse constructor and prototype properties to run JavaScript in the host Node.js process. Affected versions are <= 0.1.4 and <= 2.0.0-beta.4.
Mitigation
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.
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