CVE-2021-42338Network attack vector

Unauthenticated code execution via unvalidated login cookie

Published Nov 19, 2021 · Updated Sep 17, 2024

Authentication bypass in 4MOSAn GCB Doctor 20210708(v2.0) and earlier allows remote attackers to upload and execute arbitrary files. The login page fails to validate a cookie before processing injected code, allowing the forged cookie to bypass authentication and reach file-upload functionality. No account or user interaction is required; successful exploitation permits arbitrary system manipulation or a service interruption.

CVSS severity9.8
Critical
EPSS probability5.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in 4MOSAn GCB Doctor 20210708(v2.0) and earlier allows remote attackers to upload and execute arbitrary files. The login page fails to validate a cookie before processing injected code, allowing the forged cookie to bypass authentication and reach file-upload functionality. No account or user interaction is required; successful exploitation permits arbitrary system manipulation or a service interruption.

The record

CVE
CVE-2021-42338
Published
Nov 19, 2021
Updated
Sep 17, 2024
Vendor
4MOSAn Security Technology Co., Ltd.
Product
4MOSAn GCB Doctor
Classifications
CWE-285, CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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 <=20210708(v2.0)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

4MOSAn Security Technology Co., Ltd. · 4MOSAn GCB Doctorversion=unspecified <=20210708(v2.0)

Published CVSS scores

10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8TWCERT/CCCVSS:3.1/AV:N/AC:L/PR:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-285Improper Authorization
CWE-287Improper Authentication
T1190Exploit Public-Facing Application

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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