Is CVE-2026-9404 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-9404 being exploited in the wild.

How severe is CVE-2026-9404?

Critical severity, with a CVSS score of 9.8, published 24 May 2026.

Which products and versions are affected?

TOTOLINK A8000RU 7.1cu.643_b20200521.

Is there a fix for CVE-2026-9404?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-9404 attacked?

It is attacked over the network, in device firmware.

Am I affected by CVE-2026-9404?

Check whether you run TOTOLINK A8000RU at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-9404: Totolink A8000RU command injection in setDdnsCfg

CVE-2026-9404 · Severity: critical · CVSS 9.8 · Published 2026-05-24

A vulnerability exists in the Totolink A8000RU wireless router, a device used to provide internet connectivity and local networking. An attacker can remotely send a specially crafted request to the router's management interface to take full control of the device. This could lead to the interception of network traffic, unauthorized access to the local network, or a complete shutdown of internet services.

Technologies: TOTOLINK A8000RU. Vendors: TOTOLINK.

Quick answers

Is CVE-2026-9404 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-9404 being exploited in the wild.
How severe is CVE-2026-9404?: Critical severity, with a CVSS score of 9.8, published 24 May 2026.
Which products and versions are affected?: TOTOLINK A8000RU 7.1cu.643_b20200521.
Is there a fix for CVE-2026-9404?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-9404 attacked?: It is attacked over the network, in device firmware.
Am I affected by CVE-2026-9404?: Check whether you run TOTOLINK A8000RU at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An OS command injection vulnerability exists in the Totolink A8000RU firmware version 7.1cu.643_b20200521. The flaw is located within the 'setDdnsCfg' function of the '/cgi-bin/cstecgi.cgi' component. The application fails to properly sanitize the 'provider' parameter before passing it to the 'Uci_Set_Str' and 'CsteSystem' functions, where it is eventually executed via 'execv()'. A remote, unauthenticated attacker can exploit this by sending a crafted JSON POST request containing shell metacharacters (e.g., backticks or pipes) in the 'provider' field. Successful exploitation results in arbitrary command execution as the root user. Public exploit code is available.

Affected products

Totolink A8000RU 7.1cu.643_b20200521

Timeline

2026-05-24: disclosed: Vulnerability details and PoC published via GitHub and VulDB.
2026-05-24: advisory: CVE-2026-9404 assigned.

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.