CVE-2026-53597

HIGHPre-NVD 8.78.7
EchelonGraph scoreLOW confidence

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: secondary
8.7
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: —CVSS: 8.7Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
8.7
EG Score
8.7(low)
EPSS
—
KEV
Not listed

Published

July 16, 2026

Last Modified

July 16, 2026

Advisory Details (2)

Auto-updated Jul 16, 2026
Patch available. Sources: github_commit, github.
github Patch Available

Arbitrary code execution via JavaScript frontmatter in TypeScript loader · Advisory · microsoft/prompty · GitHub

https://github.com/microsoft/prompty/security/advisories/GHSA-c4gh-rv8h-q9vw
github_commit

commit c27402da2487 (microsoft/prompty)

Fix landed in microsoft/prompty commit c27402da2487 — awaiting tagged release

https://github.com/microsoft/prompty/commit/c27402da2487075be577f06aa79df627fb9d6853

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 3× in last 7d / 3× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-17 03:18 UTCEG score recompute
  2. 2026-07-16 15:24 UTCEG score recompute
  3. 2026-07-16 15:23 UTCMITRE cvelistV5first tracked

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Frequently asked(4)

What is CVE-2026-53597?
CVE-2026-53597 is a high vulnerability published on July 16, 2026. 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…
When was CVE-2026-53597 disclosed?
CVE-2026-53597 was first published in the National Vulnerability Database on July 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-53597?
CVE-2026-53597 has a CVSS v3 base score of 8.7 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-53597?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53597, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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