CVE-2021-38710Network attack vector

Stored XSS via unescaped SITE_NAME parameter

Published Aug 18, 2021 · Updated Aug 4, 2024

Cross-site scripting in Yclas 4.3.0 allows attackers to store script content through the install/view/form.php SITE_NAME parameter. The parameter is persisted in the database without effective validation or escaping before later page rendering, enabling script execution in a visiting user's browser. Exploitation requires network access and victim interaction with affected content; demonstrated impact is persistent script execution with confidentiality and integrity effects in the browser context.

CVSS severity4.3
Medium
EPSS probability0.64%
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 Yclas 4.3.0 allows attackers to store script content through the install/view/form.php SITE_NAME parameter. The parameter is persisted in the database without effective validation or escaping before later page rendering, enabling script execution in a visiting user's browser. Exploitation requires network access and victim interaction with affected content; demonstrated impact is persistent script execution with confidentiality and integrity effects in the browser context.

The record

CVE
CVE-2021-38710
Published
Aug 18, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

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
4.3NVDAV:N/AC:M/Au:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript

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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