CVE-2026-53597Network attack vector

Arbitrary code execution via JavaScript frontmatter

Published Jul 16, 2026 · Updated Jul 16, 2026

Code injection in Microsoft Prompty 2.0.0-alpha.1 through 2.0.0-beta.2 allows attackers to execute JavaScript via a crafted .prompty file. The TypeScript loader passes frontmatter to gray-matter without replacing its executable js and javascript engines, so parsing evaluates the block. Exploitation requires a host application or user to load an attacker-controlled prompt, and the code runs with the Node.js process's privileges.

CVSS severity8.7
High
EPSS probability0.97%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in Microsoft Prompty 2.0.0-alpha.1 through 2.0.0-beta.2 allows attackers to execute JavaScript via a crafted .prompty file. The TypeScript loader passes frontmatter to gray-matter without replacing its executable js and javascript engines, so parsing evaluates the block. Exploitation requires a host application or user to load an attacker-controlled prompt, and the code runs with the Node.js process's privileges.

The record

CVE
CVE-2026-53597
Published
Jul 16, 2026
Updated
Jul 16, 2026
Vendor
Microsoft
Product
Prompty
Classifications
CWE-94, T1204.002, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 2.0.0-alpha.1, < 2.0.0-beta.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Promptyversion=>= 2.0.0-alpha.1, < 2.0.0-beta.3

Published CVSS scores

8.7GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1204.002User Execution: Malicious File
T1059.007Command and Scripting Interpreter: JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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