CVE-2026-5688

Totolink A7100RU cstecgi.cgi setDdnsCfg os command injection

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Published Apr 6, 2026 CVSS 4.0 · 6.9 Medium EPSS 1.6% KEV · Not listed
Description
A security vulnerability has been detected in Totolink A7100RU 7.4cu.2313_b20191024. Impacted is the function setDdnsCfg of the file /cgi-bin/cstecgi.cgi. Such manipulation of the argument provider leads to os command injection. The attack may be launched remotely. The exploit has been disclosed publicly and may be used.

Analysis

AI-generated

Technical impact

The A7100RU firmware contains a flaw in the setDdnsCfg function of /cgi-bin/cstecgi.cgi. An attacker can supply crafted URL parameters that are passed to the underlying shell without proper sanitization, allowing them to execute arbitrary OS commands on the device. This vulnerability is a classic example of OS command injection (CWE‑77, CWE‑78) and can lead to remote code execution, compromising confidentiality, integrity, and availability of the device’s network traffic.

Affected Systems

Only the Totolink A7100RU routers running firmware 7.4cu.2313_b20191024 are affected. The flaw resides in the cstecgi.cgi script bundled with that firmware release. No other Totolink products or firmware versions are reported to be impacted by this defect.

Risk and Exploitability

With a CVSS base score of 6.9, the risk is moderate but the flaw allows full remote code execution. The EPSS score is 1%, indicating a low estimated probability of exploitation, though public disclosure and demonstrated exploits show it is feasible without special conditions. Because the attack vector is remote, any user connecting to the web interface from an untrusted network is potentially exposed; the vendor has not listed it in the KEV catalog, but the public availability of exploit code raises concern.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Check the current firmware version of your Totolink A7100RU router.
  • Download the latest firmware from Totolink’s official website or support portal.
  • Apply the firmware update following Totolink’s instructions and reboot the device.
  • Verify that the cstecgi.cgi setDdnsCfg endpoint is no longer vulnerable by performing a harmless command injection test or using a vendor‑provided test tool.
  • If an update cannot be applied immediately, restrict remote access to the device’s web interface (e.g., via ACLs or firewall rules) and monitor for anomalous traffic.

Generated by OpenCVE AI on May 22, 2026 at 15:24 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': 'partial'}, '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 vulnerability has been detected in Totolink A7100RU 7.4cu.2313_b20191024. Impacted is the function setDdnsCfg of the file /cgi-bin/cstecgi.cgi. Such manipulation of the argument provider leads to os command injection. The attack may be launched remotely. The exploit has been disclosed publicly and may be used.
Title Totolink A7100RU cstecgi.cgi setDdnsCfg 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': 7.5, 'vector': 'AV:N/AC:L/Au:N/C:P/I:P/A:P/E:POC/RL:ND/RC:UR'}

cvssV3_0

{'score': 7.3, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R'}

cvssV3_1

{'score': 7.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/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 8, 2026, 2:09 PM
Reserved
Apr 6, 2026, 10:26 AM

View source JSON

Updated
Apr 8, 2026, 2:09 PM

JSON

Status
Deferred
Published
Apr 6, 2026, 11:16 PM
Modified
Jul 24, 2026, 9:10 AM

View source JSON

No data.

Updated
May 22, 2026, 3:30 PM

JSON