Is this vulnerability remotely exploitable?

Yes. An attacker can remotely upload or share a malicious markdown file; exploitation occurs when another user opens it in their browser via the Markright interface.

What level of access does an attacker need?

The attacker needs the ability to submit or upload markdown content that will later be rendered by Markright. This might require an account or participation in a shared workspace, depending on how the application is deployed.

What is the safest general fix pattern?

The safest approach is to treat all markdown as untrusted, disable or restrict raw HTML, and apply a strong HTML sanitizer after rendering. Additionally, ensure that any remaining user content is contextually encoded before insertion into the page.

Severity:

HIGH RISK

(7.2)

Persistent Cross-Site Scripting (CWE-79) in Markright Markdown Handling

CVE-2021-47838

Published:

Jan 16, 2026

Status:

Awaiting Analysis

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

Recent Vulnerabilities

CWE-306

CRITICAL RISK

CRITICAL

(9.8)

Missing Authentication for Forgot-Password Email Change API (CWE-306)

Account Takeover / Loss of Account Control

February 17, 2026

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in node-sonos-http-api TTS Provider for macOS

Remote Code Execution on the Server Host

February 17, 2026

Vulnerability Type

Category:

Cross-Site Scripting (XSS)

CWE:

CWE-79

Impact:

Arbitrary JavaScript Execution / Potential Remote Code Execution via Browser

Severity:

HIGH RISK

(7.2)

CVSS Version:

3.1

Vulnerability Type

Category:

Cross-Site Scripting (XSS)

CWE:

CWE-79

Impact:

Arbitrary JavaScript Execution / Potential Remote Code Execution via Browser

Severity:

HIGH RISK

(7.2)

CVSS Version:

3.1

Catch This CVE While Code Is Being Written

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Made with Love in San Francisco

355 Bryant St. San Francisco, CA 94107, USA

Ask AI for summary of CodeAnt

Persistent Cross-Site Scripting (CWE-79) in Markright Markdown Handling

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

CRITICAL RISK

CRITICAL

(9.8)

Missing Authentication for Forgot-Password Email Change API (CWE-306)

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in node-sonos-http-api TTS Provider for macOS

Vulnerability Type

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

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