CVE-2026-20841Public exploit

User-triggered code execution via unvalidated Markdown links

Published Feb 10, 2026 · Updated Feb 10, 2026

Command injection in Microsoft Windows Notepad before 11.2512.26.0 allows attackers to execute code through a crafted Markdown link. Notepad's Markdown link handler launches an unvalidated URI scheme through a registered protocol handler, which can load and execute remote content. Exploitation requires the target user to open the Markdown file and click the link; resulting code runs with that user's privileges.

CVSS severity7.8
High
EPSS probability11.85%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in Microsoft Windows Notepad before 11.2512.26.0 allows attackers to execute code through a crafted Markdown link. Notepad's Markdown link handler launches an unvalidated URI scheme through a registered protocol handler, which can load and execute remote content. Exploitation requires the target user to open the Markdown file and click the link; resulting code runs with that user's privileges.

The record

CVE
CVE-2026-20841
Published
Feb 10, 2026
Updated
Feb 10, 2026
Vendor
Microsoft
Product
Windows Notepad
Classifications
CWE-77, T1204.001
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 10, 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=11.0.0 <11.2510

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · Windows Notepadversion=11.0.0 <11.2510

Published CVSS scores

7.8MicrosoftCVSS:3.1/AV:L/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.

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No observations available

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

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
T1204.001User Execution: Malicious Link

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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