Stored Cross-Site Scripting Vulnerability in Markup Markdown Plugin
CVE-2025-9540

4.7MEDIUM

Key Information:

Vendor

WordPress
Status
Markup Markdown
Vendor
CVE Published:
22 September 2025

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2025-9540?

The Markup Markdown WordPress plugin, prior to version 3.20.10, contains a vulnerability that allows links to include JavaScript code. This flaw enables users with contributor roles and higher permissions to execute Stored Cross-Site Scripting (XSS) attacks, potentially compromising the security of the website and its users.

Affected Version(s)

Markup Markdown 0 < 3.20.10

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2025-9540 - Proof of Concept

References

https://wpscan.com/vulnerability/79e606df-50a0-4639-b2d9-...
exploitvdb-entrytechnical-description

CVSS V3.1

Score:
4.7
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
High
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

minseok Kim
WPScan
JSON
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CVE-2025-9540 : Stored Cross-Site Scripting Vulnerability in Markup Markdown Plugin