CVE-2021-27710Public exploitNetwork attack vector

Unauthenticated command execution via unsanitized IP parameter

Published Apr 14, 2021 · Updated Aug 3, 2024

OS command injection in TOTOLINK X5000R 9.1.0u.6118_B20201102 and A720R 4.1.5cu.470_B20200911 allows remote attackers to execute commands. The setDiagnosisCfg request handler at /cgi-bin/cstecgi.cgi passes the unvalidated ip value into a command executed by glibc system(), allowing shell separators or newlines to introduce additional commands. No authentication or user interaction is required, and successful exploitation runs arbitrary commands with the router service's privileges.

CVSS severity9.8
Critical
EPSS probability7.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in TOTOLINK X5000R 9.1.0u.6118_B20201102 and A720R 4.1.5cu.470_B20200911 allows remote attackers to execute commands. The setDiagnosisCfg request handler at /cgi-bin/cstecgi.cgi passes the unvalidated ip value into a command executed by glibc system(), allowing shell separators or newlines to introduce additional commands. No authentication or user interaction is required, and successful exploitation runs arbitrary commands with the router service's privileges.

The record

CVE
CVE-2021-27710
Published
Apr 14, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-78, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 14, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8NIST NVDCVSS: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 exploitPublished

Weakness, pattern, technique

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