# CVE-2026-20841 — Microsoft Windows Notepad

> As of 2026-08-19, CVE-2026-20841 is a HIGH-severity vulnerability in Microsoft Windows Notepad, CVSS v3.1 7.8, EPSS 9.0% (95.1th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-20841, most recently “CVE-2026-20841: Command Injection in Windows Notepad Markdown Link Handling Enables Arbitrary Code Execution”.

**Last updated:** 2026-08-19

## What is CVE-2026-20841?

Improper neutralization of special elements used in a command ('command injection') in Windows Notepad App allows an unauthorized attacker to execute code locally.

The record classifies CVE-2026-20841 under weakness class [CWE-77](https://intel.threadlinqs.com/cwe/CWE-77). Its CVSS v3 base vector states that the flaw requires local access to the host, needs no prior authentication, needs a user to take an action first, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 263 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.8 — HIGH (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`)
- **EPSS (FIRST):** 9.0% probability of exploitation in the next 30 days, higher than 95.1% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 9.7/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-02-10, last modified 2026-08-19

## Is CVE-2026-20841 being exploited?

Weaponised exploit code for CVE-2026-20841 is publicly available. 10 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 37 in the Threadlinqs vulnerability feed.

- [BTtea/CVE-2026-20841-PoC](https://github.com/BTtea/CVE-2026-20841-PoC) (github)
- [patchpoint/CVE-2026-20841](https://github.com/patchpoint/CVE-2026-20841) (github)
- [atiilla/CVE-2026-20841](https://github.com/atiilla/CVE-2026-20841) (github)
- [uky007/CVE-2026-20841_notepad_analysis](https://github.com/uky007/CVE-2026-20841_notepad_analysis) (github)
- [tangent65536/CVE-2026-20841](https://github.com/tangent65536/CVE-2026-20841) (github)
- [dogukankurnaz/CVE-2026-20841-PoC](https://github.com/dogukankurnaz/CVE-2026-20841-PoC) (github)
- [hamzamalik3461/CVE-2026-20841](https://github.com/hamzamalik3461/CVE-2026-20841) (github)
- [SecureWithUmer/CVE-2026-20841](https://github.com/SecureWithUmer/CVE-2026-20841) (github)

## Affected products and versions

- [Microsoft](https://intel.threadlinqs.com/vendors/microsoft): Windows Notepad

## How to fix CVE-2026-20841

No vendor patch reference has been recorded for CVE-2026-20841 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-20841

1 tracked threat in the Threadlinqs corpus references CVE-2026-20841, either in the campaign’s CVE list or as an indicator on the campaign record.

- [CVE-2026-20841: Command Injection in Windows Notepad Markdown Link Handling Enables Arbitrary Code Execution](https://intel.threadlinqs.com/threat/TL-2026-1549) — HIGH · 2026-02-19

## Sources

Enriched from CVE.org, FIRST EPSS, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-10-10.

**Vendor advisory and patch**

- [msrc.microsoft.com — vendor advisory](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20841)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-20841
Full detection coverage and IOCs for threats exploiting CVE-2026-20841 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp