CVE-2026-73299
CVE-2026-73299 · Prompty: Server-Side Template Injection to Remote Code Execution in the @prompty/core Nunjucks Renderer
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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.
CVSS 10.0 · Critical · EPSS 1.8% · Fix available
- Published
- Updated
Stack: node
Affected products and versions
prompty
- Versions
- < 0.1.5: Affected
- >= 2.0.0-alpha.1, < 2.0.0-beta.5: Affected
No fix published
@prompty/core npm
- Affected ranges
- SEMVER: < 0.1.5
Update to 0.1.5
@prompty/core npm
- Affected ranges
- SEMVER: ≥ 2.0.0-alpha.1, < 2.0.0-beta.5
Update to 2.0.0-beta.5
Original sources
- https://github.com/microsoft/prompty/security/advisories/GHSA-w28w-gp39-m4p6
- https://github.com/microsoft/prompty/pull/404
- https://github.com/microsoft/prompty/pull/405
- https://github.com/microsoft/prompty/commit/e4a0ebf49e3a78d5d7796c8480bf9a4f0c54d19e
- https://github.com/microsoft/prompty/commit/f5c57c94a0990cca79d095c3daab661b4b1fb89f
- https://github.com/microsoft/prompty/tree/typescript/2.0.0-beta.5
- https://nvd.nist.gov/vuln/detail/CVE-2026-73299