CVE-2020-23370Network attack vector

Stored XSS via unrestricted SWF upload

Published May 10, 2021 · Updated Aug 4, 2024

Stored cross-site scripting in YzmCMS 5.6 allows remote attackers to inject arbitrary web script through a SWF upload. The common/static/plugin/ueditor/1.4.3.3/php/controller.php action parameter accepts an uploaded SWF without preventing embedded script or HTML, creating persistent content that executes when rendered. Exploitation requires low-privilege access and a victim to load the affected content; the documented impact is unauthorized script execution and integrity or confidentiality effects in that user's browser context.

CVSS severity5.4
Medium
EPSS probability0.73%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in YzmCMS 5.6 allows remote attackers to inject arbitrary web script through a SWF upload. The common/static/plugin/ueditor/1.4.3.3/php/controller.php action parameter accepts an uploaded SWF without preventing embedded script or HTML, creating persistent content that executes when rendered. Exploitation requires low-privilege access and a victim to load the affected content; the documented impact is unauthorized script execution and integrity or confidentiality effects in that user's browser context.

The record

CVE
CVE-2020-23370
Published
May 10, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 10, 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 privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.5NVDAV: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 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-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

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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