{"id":"CVE-2026-53597","summary":"Prompty: Arbitrary code execution via JavaScript frontmatter in TypeScript loader","details":"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 gray-matter without overriding executable js and javascript frontmatter engines, allowing an attacker-controlled .prompty file with ---js frontmatter to execute arbitrary JavaScript during prompt loading. This issue is fixed in version 2.0.0-beta.3.","aliases":["GHSA-c4gh-rv8h-q9vw"],"modified":"2026-07-19T03:31:06.913190597Z","published":"2026-07-16T14:54:55.075Z","database_specific":{"cwe_ids":["CWE-94"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53597.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53597.json"},{"type":"ADVISORY","url":"https://github.com/microsoft/prompty/security/advisories/GHSA-c4gh-rv8h-q9vw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53597"},{"type":"FIX","url":"https://github.com/microsoft/prompty/commit/c27402da2487075be577f06aa79df627fb9d6853"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/microsoft/prompty","events":[{"introduced":"30acb714bf68259760916c97b0c8fdaf1c5a75a0"},{"fixed":"c27402da2487075be577f06aa79df627fb9d6853"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"2.0.0-alpha.1"},{"fixed":"2.0.0-beta.3"}]}}],"versions":["python/2.0.0b2","typescript/2.0.0-beta.2","rust/2.0.0-beta.2","csharp/2.0.0-beta.2","python/2.0.0b1","typescript/2.0.0-beta.1","rust/2.0.0-beta.1","csharp/2.0.0-beta.1","rust/2.0.0-alpha.12","typescript/2.0.0-alpha.11","rust/2.0.0-alpha.11","python/2.0.0a11","csharp/2.0.0-alpha.11","csharp/2.0.0-alpha.10","rust/2.0.0-alpha.10","typescript/2.0.0-alpha.10","python/2.0.0a10","rust/2.0.0-alpha.9","typescript/2.0.0-alpha.9","python/2.0.0a9","csharp/2.0.0-alpha.9","rust/2.0.0-alpha.8","typescript/2.0.0-alpha.8","python/2.0.0a8","csharp/2.0.0-alpha.8","typescript/2.0.0-alpha.7","csharp/2.0.0-alpha.7","python/2.0.0a7","csharp/2.0.0-alpha.6","typescript/2.0.0-alpha.6","python/2.0.0a6","csharp/2.0.0-alpha.2","csharp/2.0.0-alpha.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53597.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}]}