CVE-2021-42330Network attack vector

Cross-account data access via unchecked URL parameters

Published Oct 15, 2021 · Updated Sep 16, 2024

Improper authorization in ShinHer StudyOnline System 2021 and earlier allows remote authenticated users to read and edit other users’ account data. The Teacher Edit function trusts URL parameters that select the target account without enforcing authorization for that account. A valid low-privilege login is required; exploitation exposes and alters other users’ credentials and personal information.

CVSS severity8.8
High
EPSS probability0.98%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in ShinHer StudyOnline System 2021 and earlier allows remote authenticated users to read and edit other users’ account data. The Teacher Edit function trusts URL parameters that select the target account without enforcing authorization for that account. A valid low-privilege login is required; exploitation exposes and alters other users’ credentials and personal information.

The record

CVE
CVE-2021-42330
Published
Oct 15, 2021
Updated
Sep 16, 2024
Vendor
ShinHer Information Co., LTD.
Product
ShinHer StudyOnline System
Classifications
CWE-285, T1098
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 15, 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 <=2021

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ShinHer Information Co., LTD. · ShinHer StudyOnline Systemversion=unspecified <=2021

Published CVSS scores

8.8TWCERT/CCCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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-285Improper Authorization
T1098Account Manipulation

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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