CVE-2026-53598: Microsoft Prompty

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 stayed within the prompt directory or allowed roots, allowing an attacker-controlled prompt file to read local files through absolute paths, .. traversal, or symlink escapes. This issue is fixed in versions 2.0.0-beta.2.

Affected products

• Microsoft Prompty: before 2.0.0-beta.2 (fixed in 2.0.0-beta.2)

Published 2026-07-16. Last modified 2026-07-17.