CVE-2021-39201: Authenticated cross-site scripting (XSS) in WordPress editor

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-09-09 · updated 2026-06-17
Weakness: CWE-79

Description

WordPress is a free and open-source content management system written in PHP and paired with a MySQL or MariaDB database. ### Impact The issue allows an authenticated but low-privileged user (like contributor/author) to execute XSS in the editor. This bypasses the restrictions imposed on users who do not have the permission to post `unfiltered_html`. ### Patches This has been patched in WordPress 5.8, and will be pushed to older versions via minor releases (automatic updates). It's strongly recommended that you keep auto-updates enabled to receive the fix. ### References https://wordpress.org/news/category/releases/ https://hackerone.com/reports/1142140 ### For more information If you have any questions or comments about this advisory: * Open an issue in [HackerOne](https://hackerone.com/wordpress)

Affected products

Debian Linux: 10.0, 11.0
WordPress: from 5.0 before 5.8 — fixed in 5.8

How to fix

Upgrade to a fixed version: WordPress 5.8. Check the vendor advisory for mitigations.

References

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