CVE-2021-24471Public exploitNetwork attack vector

Stored XSS via unsanitized shortcode attributes

Published Aug 16, 2021 · Updated Aug 3, 2024

Stored XSS in Embeds for YouTube before 5.2.2 allows remote authenticated users to execute scripts through crafted shortcodes. The youtube and youtube_thumb shortcode rendering paths place unvalidated and unescaped attributes into generated HTML, including event-handler injection points. Contributor access is required to store a payload, and another user must view the rendered content; the injected script then runs in that viewer’s browser context.

CVSS severity5.4
Medium
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Embeds for YouTube before 5.2.2 allows remote authenticated users to execute scripts through crafted shortcodes. The youtube and youtube_thumb shortcode rendering paths place unvalidated and unescaped attributes into generated HTML, including event-handler injection points. Contributor access is required to store a payload, and another user must view the rendered content; the injected script then runs in that viewer’s browser context.

The record

CVE
CVE-2021-24471
Published
Aug 16, 2021
Updated
Aug 3, 2024
Vendor
Embeds For YouTube Plugin Support
Product
Embeds for YouTube
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 16, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.2.2 <5.2.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Embeds For YouTube Plugin Support · Embeds for YouTubeversion=5.2.2 <5.2.2

Published CVSS scores

2.1NIST NVDAV:N/AC:H/Au:S/C:N/I:P/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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