CVE-2026-7823

Totolink A8000RU cstecgi.cgi setAppFilterCfg os command injection

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Published May 5, 2026 CVSS 4.0 · 9.3 Critical EPSS 1.8% KEV · Not listed
Description
A security flaw has been discovered in Totolink A8000RU 7.1cu.643_b20200521. Affected is the function setAppFilterCfg of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument enable results in os command injection. The attack may be launched remotely. The exploit has been released to the public and may be used for attacks.

Analysis

AI-generated

Technical impact

A flaw in the firmware of the Totolink A8000RU router allows a remote attacker to manipulate the enable argument of the cstecgi.cgi script, resulting in arbitrary operating‑system command execution. This vulnerability is classified as OS command injection, identified by CWE‑77 and CWE‑78, and carries a CVSS score of 9.3, indicating critical severity.

Affected Systems

Any A8000RU router running firmware 7.1cu.643_b20200521 is vulnerable, as the problem resides in the setAppFilterCfg function in /cgi-bin/cstecgi.cgi accessed via the web interface.

Risk and Exploitability

Exploit code has been publicly released and can be invoked remotely without local privileges, raising the real‑world likelihood of attack. The CVSS score confirms a high risk level; the EPSS score is 2%, indicating a low probability of exploitation, yet the existence of a public exploit signals that attackers can command the device at will. Although the vulnerability has not yet been listed in the CISA KEV catalog, the combination of critical severity and available exploit warrants immediate attention.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Apply the latest Totolink firmware update that patches the command‑injection flaw in setAppFilterCfg.
  • If no update is available, block external access to /cgi-bin/cstecgi.cgi by configuring firewall rules or router ACLs, preventing the CGI from being reached by remote hosts.
  • Implement input validation or strict whitelisting for the enable parameter on the router’s configuration interface so only allowed values are accepted.
  • Separate the router from critical internal networks and monitor system logs for attempts to execute shell commands via the CGI endpoint.

Generated by OpenCVE AI on October 25, 2026 at 19:46 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 a8000ru
Vendors & Products Totolink a8000ru
Type Values Removed Values Added
Description A security flaw has been discovered in Totolink A8000RU 7.1cu.643_b20200521. Affected is the function setAppFilterCfg of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument enable results in os command injection. The attack may be launched remotely. The exploit has been released to the public and may be used for attacks.
Title Totolink A8000RU cstecgi.cgi setAppFilterCfg os command injection
First Time appeared Totolink
Totolink a8000ru Firmware
Weaknesses CWE-77
CWE-78
CPEs cpe:2.3:o:totolink:a8000ru_firmware:*:*:*:*:*:*:*:*
Vendors & Products Totolink
Totolink a8000ru 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
May 5, 2026, 12:36 PM
Reserved
May 4, 2026, 10:14 PM

View source JSON

Updated
May 5, 2026, 12:36 PM

JSON

Status
Deferred
Published
May 5, 2026, 5:16 AM
Modified
Oct 26, 2026, 7:10 PM

View source JSON

No data.

Updated
Oct 25, 2026, 8:00 PM

JSON