CVE-2020-21656Public exploitNetwork attack vector

Browser script execution via stored Link content

Published Oct 6, 2021 · Updated Aug 4, 2024

Stored cross-site scripting in XYHCMS 3.6 allows remote authenticated users to execute script in another user's browser via the Link page. The public report identifies xyhai.php?s=/Link/index but does not disclose the input field, storage operation, or output context that fails to neutralize the payload. Exploitation requires low-privileged access and a victim to view the stored content; the reported effect is limited to browser-context data access and modification.

CVSS severity5.4
Medium
EPSS probability0.45%
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 XYHCMS 3.6 allows remote authenticated users to execute script in another user's browser via the Link page. The public report identifies xyhai.php?s=/Link/index but does not disclose the input field, storage operation, or output context that fails to neutralize the payload. Exploitation requires low-privileged access and a victim to view the stored content; the reported effect is limited to browser-context data access and modification.

The record

CVE
CVE-2020-21656
Published
Oct 6, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 6, 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.

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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')
T1203Exploitation for Client Execution

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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