CVE-2026-53597High▾ TwilightPrompty: Arbitrary code execution via JavaScript frontmatter in TypeScript loader
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0.2 · exploitation 0
Need a working PoC? Pro members can cast a request and our team develops one — it lands right here.
Exploit-prediction probability, daily snapshots since Jul 31.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via GHSA
0.9%
0.9% → 1.0%
The TypeScript Prompty loader used gray-matter without overriding executable frontmatter engines. gray-matter supports JavaScript frontmatter blocks such as ---js and evaluates them while parsing. An attacker-controlled .prompty file could therefore execute arbitrary JavaScript during prompt loading.
@prompty/core v2 prerelease line: >= 2.0.0-alpha.1 < 2.0.0-beta.3@prompty/[email protected]The legacy v1 JavaScript runtime had a historical hardening change for this issue. During the v2 TypeScript runtime rebuild, the loader again called gray-matter directly and the vulnerable behavior was present in the v2 prerelease packages until 2.0.0-beta.3.
Applications that load untrusted .prompty files, user-provided prompt paths, or prompt bundles from less-trusted locations could execute arbitrary JavaScript in the host Node.js process during frontmatter parsing.
Upgrade @prompty/core to 2.0.0-beta.3 or later.
The fix explicitly overrides the js and javascript gray-matter engines and rejects JavaScript frontmatter in .prompty files. Prompty frontmatter is YAML-only; executable frontmatter is unsupported. A regression test now verifies that ---js frontmatter is rejected and not evaluated.
Fixed by commit c27402da2487075be577f06aa79df627fb9d6853 and released via typescript/2.0.0-beta.3.
@prompty/core >= 2.0.0-alpha.1, < 2.0.0-beta.3Upgrade to a patched release:
@prompty/core 2.0.0-beta.3Connected by shared product, vendor, weakness, or advisory.
GHSA-w28w-gp39-m4p6Critical· 10.0Prompty: Server-Side Template Injection to Remote Code Execution in the @prompty/core Nunjucks Renderer
CVE-2025-11905Medium· 6.3A vulnerability was found in yanyutao0402 ChanCMS up to 3.3.2
CVE-2025-14730Medium· 4.7A security flaw has been discovered in CTCMS Content Management System up to 2.1.2
CVE-2025-14729Medium· 4.7A vulnerability was identified in CTCMS Content Management System up to 2.1.2
CVE-2025-10097Medium· 6.3A vulnerability was identified in SimStudioAI sim up to 1.0.0
CVE-2025-13786High· 7.3A vulnerability was detected in taosir WTCMS up to 01a5f68a3dfc2fdddb44eed967bb2d4f60487665