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CVE Record

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

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).

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-24471 is a stored cross-site scripting issue in the YouTube Embed WordPress plugin before 5.2.2. A contributor-level user could save unsafe shortcode attributes, or unsafe YouTube metadata could be embedded when an API key is configured. The main business risk is script execution in visitors' or administrators' browsers from trusted site content.

Executive priority

Treat as a near-term CMS hygiene issue, not an emergency without exploitation evidence. Prioritize internet-facing WordPress sites, high-traffic properties, and sites with many content contributors.

Technical view

The plugin failed to validate, sanitize, or escape several youtube and youtube_thumb shortcode attributes. Sources also describe stored XSS via embedded video title or description when API-key integration is configured. The issue is categorized as CWE-79. No CVSS score is provided in the bundle.

Likely exposure

WordPress sites running YouTube Embed versions before 5.2.2 are the likely exposure. Risk is higher where contributor-level users can create content, shortcodes are used broadly, or the plugin is configured with a YouTube API key.

Exploitation context

The bundle does not show CISA KEV listing or active exploitation evidence. Exploitation appears to require content contribution rights or unsafe external video metadata being embedded under the plugin's API-key configuration.

Researcher notes

Evidence is limited to the CVE description and WPScan reference in the source bundle. The affected attribute list is specific, but no CVSS vector, exploit status, or detailed vendor advisory is included here.

Mitigation direction

  • Update YouTube Embed to version 5.2.2 or later.
  • Check vendor or WordPress plugin guidance for current remediation details.
  • Restrict contributor-level publishing and shortcode use until remediated.
  • Disable or remove the plugin if it cannot be updated safely.
  • Review API-key configured embeds for unsafe imported metadata.

Validation and detection

  • Inventory WordPress sites for the YouTube Embed plugin and version.
  • Confirm whether any installed version is older than 5.2.2.
  • Identify users with contributor or higher content creation rights.
  • Review usage of youtube and youtube_thumb shortcodes in posts and pages.
  • Check whether the plugin is configured with a YouTube API key.
Prepared
Confidence
medium
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-79: User-session and phishing behavior lookup

Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2021-24471 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
UnknownYouTube Embed5.2.2Listed
Weakness

CWE details

CWE-79

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-79 · source CWE mapping

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs