Critical severity10.0NVD Advisory· Published Aug 12, 2026· Updated Aug 12, 2026
CVE-2026-73299
CVE-2026-73299
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.
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Affected products
1Patches
Vulnerability mechanics
References
6- github.com/microsoft/prompty/commit/e4a0ebf49e3a78d5d7796c8480bf9a4f0c54d19envd
- github.com/microsoft/prompty/commit/f5c57c94a0990cca79d095c3daab661b4b1fb89fnvd
- github.com/microsoft/prompty/pull/404nvd
- github.com/microsoft/prompty/pull/405nvd
- github.com/microsoft/prompty/security/advisories/GHSA-w28w-gp39-m4p6nvd
- github.com/microsoft/prompty/tree/typescript/2.0.0-beta.5nvd
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