CVE-2021-29447: WordPress Authenticated XXE attack when installation is running PHP 8

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 85.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-04-15 · updated 2026-06-17
Weakness: CWE-611

Description

Wordpress is an open source CMS. A user with the ability to upload files (like an Author) can exploit an XML parsing issue in the Media Library leading to XXE attacks. This requires WordPress installation to be using PHP 8. Access to internal files is possible in a successful XXE attack. This has been patched in WordPress version 5.7.1, along with the older affected versions via a minor release. We strongly recommend you keep auto-updates enabled.

Affected products

Debian Linux: 9.0, 10.0
WordPress: from 5.6.0 before 5.7.1 — fixed in 5.7.1

How to fix

Upgrade to a fixed version: WordPress 5.7.1. Check the vendor advisory for mitigations.

References

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