CVE-2021-42872Public exploitNetwork attack vector

Unauthenticated code execution via NoticeUrl injection

Published May 31, 2022 · Updated Jul 9, 2026

Command injection in TOTOLINK EX1200T firmware 4.1.2cu.5215 allows remote attackers to execute arbitrary code over the network. The setNoticeCfg function in lib/cste_modules/system.so incorporates the NoticeUrl value from a cstecgi.cgi request into a shell command without neutralizing embedded newline-delimited commands. No authentication or user interaction is required, and successful exploitation executes commands with the vulnerable service's privileges.

CVSS severity9.8
Critical
EPSS probability6.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in TOTOLINK EX1200T firmware 4.1.2cu.5215 allows remote attackers to execute arbitrary code over the network. The setNoticeCfg function in lib/cste_modules/system.so incorporates the NoticeUrl value from a cstecgi.cgi request into a shell command without neutralizing embedded newline-delimited commands. No authentication or user interaction is required, and successful exploitation executes commands with the vulnerable service's privileges.

The record

CVE
CVE-2021-42872
Published
May 31, 2022
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-78, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 31, 2022CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record 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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C

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 exploitPublished

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Command and Scripting Interpreter: Unix Shell

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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