CVE-2026-5994

Totolink A7100RU CGI cstecgi.cgi setTelnetCfg os command injection

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Published Apr 10, 2026 CVSS 4.0 · 9.3 Critical EPSS 1.8% KEV · Not listed
Description
A security flaw has been discovered in Totolink A7100RU 7.4cu.2313_b20191024. This issue affects the function setTelnetCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Performing a manipulation of the argument telnet_enabled results in os command injection. The attack is possible to be carried out remotely. The exploit has been released to the public and may be used for attacks.

Analysis

AI-generated

Technical impact

The vulnerability resides in the setTelnetCfg function of the cstecgi.cgi script on Totolink A7100RU routers. An attacker can manipulate the telnet_enabled parameter to inject arbitrary OS commands. Successful exploitation gives full control over the device’s operating system, allowing data theft, device takeover, or further network compromise.

Affected Systems

The flaw affects the Totolink A7100RU router running firmware version 7.4cu.2313_b20191024. No other firmware revisions are listed in the CNA data; systems running this specific build are therefore at risk.

Risk and Exploitability

With a CVSS score of 9.3 the vulnerability is high severity. The EPSS score is 2%, but the publicly released exploit and absence from the KEV catalog do not mitigate its danger. The attack vector is remote, using crafted HTTP requests to the CGI handler; no special privileges are required, and any host able to reach the router’s management interface can exploit the flaw.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Update the router firmware to a version that fixes the OS command injection vulnerability, using the latest release from Totolink's support site.
  • If a firmware update is unavailable, disable the remote Telnet service by setting telnet_enabled to 0 in the router’s configuration.
  • Restrict external access to the router’s CGI interface by placing it behind a firewall or disabling management over public networks.
  • Monitor the device for anomalous outbound traffic or execution of unexpected commands, and investigate any suspicious activity promptly.

Generated by OpenCVE AI on October 25, 2026 at 20:50 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}
Type Values Removed Values Added
First Time appeared Totolink a7100ru
Vendors & Products Totolink a7100ru
Type Values Removed Values Added
Description A security flaw has been discovered in Totolink A7100RU 7.4cu.2313_b20191024. This issue affects the function setTelnetCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Performing a manipulation of the argument telnet_enabled results in os command injection. The attack is possible to be carried out remotely. The exploit has been released to the public and may be used for attacks.
Title Totolink A7100RU CGI cstecgi.cgi setTelnetCfg os command injection
First Time appeared Totolink
Totolink a7100ru Firmware
Weaknesses CWE-77
CWE-78
CPEs cpe:2.3:o:totolink:a7100ru_firmware:*:*:*:*:*:*:*:*
Vendors & Products Totolink
Totolink a7100ru Firmware
References
Metrics cvssV2_0

{'score': 10, 'vector': 'AV:N/AC:L/Au:N/C:C/I:C/A:C/E:POC/RL:ND/RC:UR'}

cvssV3_0

{'score': 9.8, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R'}

cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R'}

cvssV4_0

{'score': 9.3, 'vector': 'CVSS: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'}
Weaknesses
  • CWE-77

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

  • CWE-78

    Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Sources

Status
PUBLISHED
Assigner
VulDB
Published
Updated
Apr 10, 2026, 5:06 PM
Reserved
Apr 9, 2026, 12:49 PM

View source JSON

Updated
Apr 10, 2026, 5:06 PM

JSON

Status
Deferred
Published
Apr 10, 2026, 1:16 AM
Modified
Oct 26, 2026, 9:10 PM

View source JSON

No data.

Updated
Oct 25, 2026, 9:00 PM

JSON