CVE-2026-9457
Published: 25 May 2026
Summary
CVE-2026-9457 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 20.6% 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
CVE-2026-9457 affects the Totolink A8000RU router running firmware version 7.1cu.643_b20200521. The flaw resides in the UploadFirmwareFile function within the /cgi-bin/cstecgi.cgi endpoint of the Web Management Interface, where improper handling of the FileName argument enables OS command injection. The issue is tracked under CWE-77 and CWE-78 and carries a CVSS 4.0 score of 8.9.
Remote, unauthenticated attackers can supply a crafted FileName value to execute arbitrary operating-system commands on the device. Successful exploitation grants full control over the router, including the ability to alter configuration, intercept traffic, or pivot into attached networks. The attack requires no user interaction and can be launched over the network.
Publicly available references, including a detailed disclosure on GitHub and entries in the Vuldb database, confirm that exploit code has been released. The vendor site is listed among the references, yet no specific patch, firmware update, or mitigation guidance is documented in the available sources. The EPSS score remains flat at 0.0125 with no observed rise, indicating limited exploitation interest to date.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-31677
Vulnerability details
A vulnerability was determined in Totolink A8000RU 7.1cu.643_b20200521. The affected element is the function UploadFirmwareFile of the file /cgi-bin/cstecgi.cgi of the component Web Management Interface. This manipulation of the argument FileName causes os command injection. The attack is possible to…
more
be carried out remotely. The exploit has been publicly disclosed and may be utilized.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct OS command injection in remotely accessible web management interface enables T1190 (public-facing app exploitation) and T1059.004 (Unix shell command execution).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation and sanitization of the FileName argument in UploadFirmwareFile to block OS command injection via cstecgi.cgi.
Enforces access control on the Web Management Interface so that unauthenticated remote callers cannot invoke firmware-upload functions.
Restricts network reachability of the router's management interface, limiting the remote attack surface that enables unauthenticated command injection.