CVE-2026-5994Public exploitNetwork attack vector

Unauthenticated command execution via telnet_enabled substitution

Published Apr 10, 2026 · Updated Apr 10, 2026

OS command injection in TOTOLINK A7100RU 7.4cu.2313_b20191024 allows remote attackers to execute arbitrary commands via HTTP. The setTelnetCfg handler in /cgi-bin/cstecgi.cgi reads telnet_enabled, formats it with snprintf into a command string, and passes it through CsteSystem to execv without neutralizing command substitutions. No authentication or user interaction is required, and injected commands run with the router CGI process's privileges.

CVSS severity9.8
Critical
EPSS probability1.80%
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 A7100RU 7.4cu.2313_b20191024 allows remote attackers to execute arbitrary commands via HTTP. The setTelnetCfg handler in /cgi-bin/cstecgi.cgi reads telnet_enabled, formats it with snprintf into a command string, and passes it through CsteSystem to execv without neutralizing command substitutions. No authentication or user interaction is required, and injected commands run with the router CGI process's privileges.

The record

CVE
CVE-2026-5994
Published
Apr 10, 2026
Updated
Apr 10, 2026
Vendor
TOTOLINK
Product
A7100RU
Classifications
CWE-77, CWE-78, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 10, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=7.4cu.2313_b20191024

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

TOTOLINK · A7100RUversion=7.4cu.2313_b20191024

Published CVSS scores

9.8VulDB CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0VulDB CNAAV:N/AC:L/Au:N/C:C/I:C/A:C
8.9VulDB CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P

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.

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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-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
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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