{"id":"CVE-2026-73299","title":"Prompty is a markdown file format (.prompty) for LLM prompts","summary":"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-controll…","severity":"critical","cvss":10,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","cwe":["CWE-94","CWE-1336"],"vendor":"microsoft","product":"prompty","affected":["prompty < 0.1.5","prompty >= 2.0.0-alpha.1, < 2.0.0-beta.5"],"published":"2026-08-12","updated":"2026-09-09","sourceUpdated":"2026-09-09T21:02:22.660","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-73299","references":[{"url":"https://github.com/microsoft/prompty/commit/e4a0ebf49e3a78d5d7796c8480bf9a4f0c54d19e","label":"security-advisories@github.com"},{"url":"https://github.com/microsoft/prompty/commit/f5c57c94a0990cca79d095c3daab661b4b1fb89f","label":"security-advisories@github.com"},{"url":"https://github.com/microsoft/prompty/pull/404","label":"security-advisories@github.com"},{"url":"https://github.com/microsoft/prompty/pull/405","label":"security-advisories@github.com"},{"url":"https://github.com/microsoft/prompty/security/advisories/GHSA-w28w-gp39-m4p6","label":"security-advisories@github.com"},{"url":"https://github.com/microsoft/prompty/tree/typescript/2.0.0-beta.5","label":"security-advisories@github.com"}],"tags":["nvd","cve.org"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-08-12T18:53:50.277151Z"},"ingestedAt":"2026-09-14T12:29:35.090Z","epss":0.01215,"epssPercentile":0.66758,"slug":"CVE-2026-73299","body":"## Overview\n\nPrompty 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":55,"depthScoreParts":{"impact":55,"likelihood":0.2,"exploitation":0,"ransomware":0},"changes":[]}