CVE-2026-7136
Published: 27 April 2026
Summary
CVE-2026-7136 is a high-severity Command Injection (CWE-77) vulnerability in Totolink A8000RU (inferred from references). Its CVSS base score is 8.9 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 24.7% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and SI-10 (Information Input Validation).
Deeper analysis
A weakness has been identified in the Totolink A8000RU router running firmware version 7.1cu.643_b20200521. The issue resides in the setDmzCfg function within the /cgi-bin/cstecgi.cgi file of the CGI Handler component, where improper handling of the wanIdx argument enables operating system command injection. The vulnerability is tracked under CVE-2026-7136 with a CVSS 4.0 score of 8.9 and is associated with CWE-77 and CWE-78.
The flaw can be exploited remotely by unauthenticated attackers over the network without user interaction, allowing them to execute arbitrary operating system commands on the device. Public exploit code has been released, increasing the potential for automated or targeted attacks against exposed routers.
The provided references consist primarily of vulnerability disclosure entries and a proof-of-concept repository, with no specific mitigation guidance or patch details from the vendor. The associated EPSS scores remain low, moving only from 0.0122 to a peak of 0.0125.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-25874
Vulnerability details
A weakness has been identified in Totolink A8000RU 7.1cu.643_b20200521. Affected by this issue is the function setDmzCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Executing a manipulation of the argument wanIdx can lead to os command injection. The…
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attack may be launched remotely. The exploit has been made available to the public and could be used for attacks.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability is a command injection in a public-facing CGI web interface (T1190: Exploit Public-Facing Application), enabling unauthenticated remote OS command execution on the router's likely Unix-based OS (T1059.004: Unix Shell).
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly blocks manipulation of the wanIdx argument in setDmzCfg before it reaches the OS command interpreter.
Enforces access restrictions on the /cgi-bin/cstecgi.cgi endpoint so unauthenticated remote callers cannot invoke the vulnerable function.
Boundary-protection rules can deny external network access to the router's management CGI interface, limiting remote exploit reach.