CVE-2021-24471: YouTube Embed < 5.2.2 - Contributor+ Stored XSS

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-08-16 · updated 2026-06-17
Weakness: CWE-79

Description

The YouTube Embed WordPress plugin before 5.2.2 does not validate, escape or sanitise some of its shortcode attributes, leading to Stored XSS issues by 1. using w, h, controls, cc_lang, color, language, start, stop, or style parameter of youtube shortcode, 2. by using style, class, rel, target, width, height, or alt parameter of youtube_thumb shortcode, or 3. by embedding a video whose title or description contains XSS payload (if API key is configured).

Affected products

YouTube Embed: before 5.2.2 — fixed in 5.2.2

How to fix

Upgrade to a fixed version: YouTube Embed 5.2.2. Check the vendor advisory for mitigations.

References

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