Microsoft Prompty vulnerabilities

3 CVEs affecting Microsoft Prompty, 0 known to be exploited (CISA KEV), with EPSS scores. Latest: CVE-2026-73299, published 2026-08-12.

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Known exploited (CISA KEV) first, then by EPSS exploit probability.

• CVE-2026-73299, published 2026-08-12. Critical severity, CVSS 10.0. EPSS: 1.8% chance of exploitation in the next 30 days. 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…
• CVE-2026-53598, published 2026-07-16. High severity, CVSS 7.5. EPSS: 1.3% chance of exploitation in the next 30 days. Prompty is a markdown file format (.prompty) for LLM prompts. Prior to 2.0.0-beta.2, Prompty loaders expanded ${file:...} references in .prompty frontmatter without enforcing that resolved paths…
• CVE-2026-53597, published 2026-07-16. High severity, CVSS 8.7. EPSS: 1% chance of exploitation in the next 30 days. Prompty is a markdown file format (.prompty) for LLM prompts. From 2.0.0-alpha.1 until 2.0.0-beta.3, the @prompty/core TypeScript loader in runtime/typescript/packages/core/src/core/loader.ts used…