---
id: CVE-2021-47839
title: >-
  Marky 0.0.1 contains a persistent cross-site scripting vulnerability that
  allows attackers to inject malicious scripts into markdown files
summary: >-
  Marky 0.0.1 contains a persistent cross-site scripting vulnerability that
  allows attackers to inject malicious scripts into markdown files. Attackers
  can upload crafted markdown files with embedded JavaScript payloads that
  execute when t…
severity: high
cvss: 7.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N'
cwe:
  - CWE-79
  - CWE-79
published: '2026-01-16'
updated: '2026-06-30'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-47839'
references:
  - url: 'https://github.com/vesparny/marky'
    label: disclosure@vulncheck.com
  - url: 'https://imgur.com/a/qclfrUx'
    label: disclosure@vulncheck.com
  - url: 'https://www.exploit-db.com/exploits/49831'
    label: disclosure@vulncheck.com
  - url: 'https://www.vulncheck.com/advisories/marky-persistent-cross-site-scripting'
    label: disclosure@vulncheck.com
  - url: 'https://access.redhat.com/security/cve/CVE-2021-47839'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2430451'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-47839.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://www.vulncheck.com/advisories/marky-persistent-cross-site-scripting'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00471
epssPercentile: 0.38122
ingestedAt: '2026-06-30T13:26:50.499Z'
---

## Overview

Marky 0.0.1 contains a persistent cross-site scripting vulnerability that allows attackers to inject malicious scripts into markdown files. Attackers can upload crafted markdown files with embedded JavaScript payloads that execute when the file is opened, potentially enabling remote code execution.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.