GHSA-w28w-gp39-m4p6Critical· 10.0▾ MidnightPrompty: Server-Side Template Injection to Remote Code Execution in the @prompty/core Nunjucks Renderer
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 55 · likelihood 0 · exploitation 0
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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.
@prompty/core versions <= 0.1.4@prompty/core versions <= 2.0.0-beta.4Applications 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.
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.
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/core <= 0.1.4@prompty/core >= 2.0.0-alpha.1, <= 2.0.0-beta.4Upgrade to a patched release:
@prompty/core 0.1.5@prompty/core 2.0.0-beta.5Connected by shared product, vendor, weakness, or advisory.
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