CVE-2021-24540Public exploitNetwork attack vector

Contributor-level stored XSS via unescaped shortcode parameters

Published Aug 16, 2021 · Updated Aug 3, 2024

Stored XSS in WonderPlugin Wonder Video Embed before 1.8 allows remote authenticated users to inject scripts through a video shortcode. The wonderplugin_video shortcode emits attacker-controlled iframe, MP4, WebM, and style-related attributes without escaping them for HTML output. Contributor access is sufficient; the stored script runs when another user views the crafted post and can act in that user's browser context.

CVSS severity5.4
Medium
EPSS probability0.62%
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 WonderPlugin Wonder Video Embed before 1.8 allows remote authenticated users to inject scripts through a video shortcode. The wonderplugin_video shortcode emits attacker-controlled iframe, MP4, WebM, and style-related attributes without escaping them for HTML output. Contributor access is sufficient; the stored script runs when another user views the crafted post and can act in that user's browser context.

The record

CVE
CVE-2021-24540
Published
Aug 16, 2021
Updated
Aug 3, 2024
Vendor
WonderPlugin
Product
Wonder Video Embed
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

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Is a vulnerable build present?

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

  1. Affected versionversion=1.8 <1.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

WonderPlugin · Wonder Video Embedversion=1.8 <1.8

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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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