CVE-2021-47838

HIGH

Markright 1.0 - Stored Cross-Site Scripting via Crafted Markdown Files

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-47838. PoCs published by TaurusOmar.

AI-analyzed exploit summary This exploit demonstrates a persistent XSS vulnerability in Markright 1.0, allowing an attacker to execute arbitrary JavaScript code via a malicious markdown file. The payload includes a reverse shell attempt and a calculator execution, leveraging the `onerror` event of an audio tag.

Description

Markright 1.0 contains a persistent cross-site scripting vulnerability that allows attackers to embed malicious payloads in markdown files. Attackers can upload specially crafted markdown files that execute arbitrary JavaScript when opened, potentially enabling remote code execution on the victim's system.

Exploits (1)

exploitdb WORKING POC
by TaurusOmar · javascriptwebappsmultiple
https://www.exploit-db.com/exploits/49834

This exploit demonstrates a persistent XSS vulnerability in Markright 1.0, allowing an attacker to execute arbitrary JavaScript code via a malicious markdown file. The payload includes a reverse shell attempt and a calculator execution, leveraging the `onerror` event of an audio tag.

Classification
Working Poc 90%
Attack Type
Xss
Complexity
Trivial
Reliability
Reliable
Target: Markright 1.0
No auth needed
Prerequisites: Victim must open a malicious markdown file in Markright
MITRE ATT&CK
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (4)

Core 4
Core References
Exploit, Third Party Advisory exploit
https://www.exploit-db.com/exploits/49834
Various Sources product
https://github.com/dvcrn/markright
Various Sources exploit
https://imgur.com/a/VOsgKbZ

Scores

CVSS v3 7.2
EPSS 0.0004
EPSS Percentile 13.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

CWE
CWE-79
Status published
Published Jan 16, 2026
Tracked Since Feb 18, 2026