CVE-2021-42890Public exploitNetwork attack vector

Unauthenticated command execution via hostTime injection

Published Jun 3, 2022 · Updated Aug 4, 2024

OS command injection in TOTOLINK EX1200T 4.1.2cu.5215 allows remote attackers to execute arbitrary commands via a crafted hostTime value. The NTPSyncWithHost handler in system.so passes shell metacharacters from hostTime through the cstecgi.cgi management endpoint, as demonstrated by a command that writes process output to a web-accessible file. No authentication or user interaction is required, and successful exploitation permits commands to read or modify data and interrupt device operation.

CVSS severity9.8
Critical
EPSS probability1.90%
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 EX1200T 4.1.2cu.5215 allows remote attackers to execute arbitrary commands via a crafted hostTime value. The NTPSyncWithHost handler in system.so passes shell metacharacters from hostTime through the cstecgi.cgi management endpoint, as demonstrated by a command that writes process output to a web-accessible file. No authentication or user interaction is required, and successful exploitation permits commands to read or modify data and interrupt device operation.

The record

CVE
CVE-2021-42890
Published
Jun 3, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-78, T1059
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 3, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
T1059Command and Scripting Interpreter

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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