What’s Vulnerable › Vulnerabilities

CVE-2021-24241: Advanced Custom Field Pro < 5.9.1 - Reflected Cross-Site Scripting (XSS)

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-04-22 · updated 2026-06-17
• Weakness: CWE-79

Description

The Advanced Custom Fields Pro WordPress plugin before 5.9.1 did not properly escape the generated update URL when outputting it in an attribute, leading to a reflected Cross-Site Scripting issue in the update settings page.

Affected products

• WP Engine Advanced Custom Fields: before 5.9.1 — fixed in 5.9.1

How to fix

Upgrade to a fixed version: WP Engine Advanced Custom Fields 5.9.1. Check the vendor advisory for mitigations.

References

• https://github.com/jdordonezn/Reflected-XSS-in-WordPress-for-ACF-PRO-before-5.9.1-plugin/issues/1
• https://wpscan.com/vulnerability/d1e9c995-37bd-4952-b88e-945e02e3c83f
• https://www.advancedcustomfields.com/blog/acf-5-9-1-release/
• https://github.com/jdordonezn/Reflected-XSS-in-WordPress-for-ACF-PRO-before-5.9.1-plugin/issues/1
• https://wpscan.com/vulnerability/d1e9c995-37bd-4952-b88e-945e02e3c83f
• https://www.advancedcustomfields.com/blog/acf-5-9-1-release/

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