CVE-2021-4251Network attack vector

Cross-site scripting via unescaped full URL

Published Dec 18, 2022 · Updated Apr 15, 2025

Cross-site scripting in the as include.cdn.php component allows remote authenticated users to inject script through a crafted URL. The getFullURL JavaScript helper embeds the server-generated full URL directly inside a single-quoted string without HTML escaping. A victim must load a page containing the attacker-controlled URL; injected script then runs in that visitor's browser under the application's origin.

CVSS severity6.1
Medium
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in the as include.cdn.php component allows remote authenticated users to inject script through a crafted URL. The getFullURL JavaScript helper embeds the server-generated full URL directly inside a single-quoted string without HTML escaping. A victim must load a page containing the attacker-controlled URL; injected script then runs in that visitor's browser under the application's origin.

The record

CVE
CVE-2021-4251
Published
Dec 18, 2022
Updated
Apr 15, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-707
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 18, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
3.5VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-707Improper Neutralization

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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