CVE-2026-5688
Published: 06 April 2026
Summary
CVE-2026-5688 is a medium-severity Command Injection (CWE-77) vulnerability in Totolink A7100RU (inferred from references). Its CVSS base score is 6.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 21.1% 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 IA-8 (Identification and Authentication (Non-organizational Users)) and SI-10 (Information Input Validation).
Deeper analysis
A security vulnerability identified as CVE-2026-5688 affects the Totolink A7100RU router running firmware version 7.4cu.2313_b20191024. The issue resides in the setDdnsCfg function within /cgi-bin/cstecgi.cgi, where improper handling of the provider argument enables OS command injection. The flaw is tracked under CWE-77 and CWE-78 and carries a CVSS 4.0 score of 6.9, reflecting network-accessible attack vectors with low complexity.
Remote, unauthenticated attackers can supply crafted input to the provider parameter and execute arbitrary operating system commands on the device. Successful exploitation yields limited effects on confidentiality, integrity, and availability of the affected router, with no requirement for user interaction.
Publicly available references include exploit details hosted on GitHub and multiple Vuldb entries, confirming that proof-of-concept code has been disclosed. The associated EPSS score has risen from a low baseline to a recorded peak of 0.0486, indicating increased exploitation interest following publication. No vendor advisory or patch information is detailed in the provided references.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-19547
Vulnerability details
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…
more
disclosed publicly and may be used.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
OS command injection in public-facing router web CGI enables remote unauthenticated arbitrary command execution, mapping to T1190 (Exploit Public-Facing Application) and T1059.004 (Unix Shell).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates the OS command injection vulnerability by identifying, patching, and verifying remediation of the insufficient input sanitization flaw in the setDdnsCfg function.
Enforces validation of untrusted inputs like the 'provider' argument in the vulnerable CGI script to block command injection attempts.
Requires identification and authentication for non-organizational users accessing the vulnerable /cgi-bin/cstecgi.cgi endpoint, preventing unauthenticated remote exploitation.