CVE-2026-54703Public exploitHinoki check available

Arbitrary file overwrite via unchecked updateMarkdown target

Published Oct 14, 2026 · Updated Oct 14, 2026

Arbitrary file write in shd101wyy Markdown Preview Enhanced before 0.8.30 allows attackers to overwrite files via preview messages. The _crossnote.updateMarkdown command passes an attacker-controlled URI and content to vscode.workspace.fs.writeFile without checking that the target belongs to the current Markdown preview. Exploitation requires a separate JavaScript execution path inside an opened preview webview, and writes are limited by the VS Code user's operating-system permissions.

CVSS severity5.8
Medium
EPSS probability0.22%
Next 30 days · Oct 18, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Arbitrary file write in shd101wyy Markdown Preview Enhanced before 0.8.30 allows attackers to overwrite files via preview messages. The _crossnote.updateMarkdown command passes an attacker-controlled URI and content to vscode.workspace.fs.writeFile without checking that the target belongs to the current Markdown preview. Exploitation requires a separate JavaScript execution path inside an opened preview webview, and writes are limited by the VS Code user's operating-system permissions.

The record

CVE
CVE-2026-54703
Published
Oct 14, 2026
Updated
Oct 14, 2026
Vendor
shd101wyy
Product
Markdown Preview Enhanced
Classifications
CWE-73, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 14, 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=< 0.8.30

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

shd101wyy · Markdown Preview Enhancedversion=< 0.8.30

Published CVSS scores

5.8GitHub_MCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-73External Control of File Name or Path
T1203Exploitation for Client Execution

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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