CVE-2021-22849Network attack vector

Stored script execution via unfiltered editor input

Published Jan 22, 2021 · Updated Sep 16, 2024

Stored cross-site scripting in Hyweb HyCMS-J1 7.4.3 and earlier allows remote authenticated users to inject JavaScript through backend editing. The backend editing function stores content without filtering special characters, causing injected script to execute when another user renders it. Authentication and subsequent user interaction are required; the script can read or modify browser-accessible data within the viewer's session.

CVSS severity4.6
Medium
EPSS probability0.51%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in Hyweb HyCMS-J1 7.4.3 and earlier allows remote authenticated users to inject JavaScript through backend editing. The backend editing function stores content without filtering special characters, causing injected script to execute when another user renders it. Authentication and subsequent user interaction are required; the script can read or modify browser-accessible data within the viewer's session.

The record

CVE
CVE-2021-22849
Published
Jan 22, 2021
Updated
Sep 16, 2024
Vendor
Hyweb Technology Co., Ltd.
Product
HyCMS-J1
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 22, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=7.4.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Hyweb Technology Co., Ltd. · HyCMS-J1version=unspecified <=7.4.3

Published CVSS scores

4.6TWCERT/CCCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
3.5NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/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
Privilegesauthenticated
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/JScript

Public exploit references

No public exploit references are available in this record.

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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