CVE-2020-21643Public exploitNetwork attack vector

Reflected script execution via unvalidated JSONP callback

Published Apr 28, 2023 · Updated Jan 31, 2025

Reflected XSS in HongCMS 3.0 allows remote attackers to execute script in a victim's browser via the /ajax/myshop callback parameter. The endpoint places the callback value directly before JSON-encoded response data, causing crafted event-handler markup to be returned as executable JSONP content. No authentication is required, but a victim must load the crafted URL; execution remains confined to the browser's HongCMS origin.

CVSS severity6.1
Medium
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in HongCMS 3.0 allows remote attackers to execute script in a victim's browser via the /ajax/myshop callback parameter. The endpoint places the callback value directly before JSON-encoded response data, causing crafted event-handler markup to be returned as executable JSONP content. No authentication is required, but a victim must load the crafted URL; execution remains confined to the browser's HongCMS origin.

The record

CVE
CVE-2020-21643
Published
Apr 28, 2023
Updated
Jan 31, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 31, 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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.001User Execution: Malicious Link

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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