Prompty: Arbitrary code execution via JavaScript frontmatter in TypeScript loader

Description

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.

Recommendation

Update the @prompty/core package to the latest compatible version. Followings are version details:

• Affected version(s): >= 2.0.0-alpha.1, < 2.0.0-beta.3
• Patched version(s): 2.0.0-beta.3

References

• GHSA-c4gh-rv8h-q9vw
• CVE-2026-53597
• CWE-94
• CAPEC-310
• OWASP 2021-A3
• OWASP 2021-A6

Related Issues

• Prompty: Arbitrary file read via file reference expansion - CVE-2026-53598
• HAX CMS: Stored XSS via '<video-player>' component allows arbitrary JavaScript execution and token theft - CVE-2026-46496
• Arbitrary code execution in protobufjs - CVE-2026-41242
• DbGate: Unauthenticated Remote Code Execution via JSON Script Runner - CVE-2026-47668

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Tags:

npm

@prompty/core