CVE-2026-50733Public exploitNetwork attack vector

Arbitrary code execution via WaveDrom eval

Published Jun 5, 2026 · Updated Jun 5, 2026

Code injection in shd101wyy Markdown Preview Enhanced before 0.8.28 allows remote attackers to execute JavaScript through crafted markdown. The WaveDrom renderer passes raw fenced-block text to window.eval(), while preserved WaveDrom data scripts reach bundled eva() helpers in preview, presentation, and export paths. A victim must preview or export the document, after which injected code can invoke the extension host to write arbitrary files.

CVSS severity8.6
High
EPSS probability0.53%
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 shd101wyy Markdown Preview Enhanced before 0.8.28 allows remote attackers to execute JavaScript through crafted markdown. The WaveDrom renderer passes raw fenced-block text to window.eval(), while preserved WaveDrom data scripts reach bundled eva() helpers in preview, presentation, and export paths. A victim must preview or export the document, after which injected code can invoke the extension host to write arbitrary files.

The record

CVE
CVE-2026-50733
Published
Jun 5, 2026
Updated
Jun 5, 2026
Vendor
shd101wyy
Product
Markdown Preview Enhanced
Classifications
CWE-95, T1204.002, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=0 <0.8.28

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

shd101wyy · Markdown Preview Enhancedversion=0 <0.8.28

Published CVSS scores

8.6VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
8.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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 exploitPublished

Weakness, pattern, technique

CWE-95Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')
T1204.002Malicious File
T1059.007JavaScript/JScript

Public exploit references

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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