Is CVE-2026-9387 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-9387 being exploited in the wild.

How severe is CVE-2026-9387?

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-2026-9387?

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-2026-9387 attacked?

It is attacked over the network, in device firmware.

Am I affected by CVE-2026-9387?

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-2026-9387: Totolink A8000RU command injection in setUpgradeFW

CVE-2026-9387 · Severity: critical · CVSS 9.8 · Published 2026-05-24

A critical security vulnerability exists in the Totolink A8000RU wireless router, a device used to provide internet connectivity in homes and small offices. An attacker can remotely take full control of the router by sending a specially crafted request to its web management interface. This could allow an unauthorized user to intercept network traffic, disrupt internet service, or use the device as a foothold to attack other devices on the local network.

Technologies: TOTOLINK A8000RU. Vendors: TOTOLINK.

Quick answers

Is CVE-2026-9387 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-9387 being exploited in the wild.
How severe is CVE-2026-9387?: 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-2026-9387?: 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-2026-9387 attacked?: It is attacked over the network, in device firmware.
Am I affected by CVE-2026-9387?: 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 'setUpgradeFW' function of the '/cgi-bin/cstecgi.cgi' component. The application fails to properly sanitize the 'resetFlags' argument before passing it to 'snprintf' and subsequently executing it via 'execv()' through the 'CsteSystem' function. A remote, unauthenticated attacker can exploit this by sending a crafted POST request containing shell metacharacters (e.g., backticks) in the 'resetFlags' parameter. Successful exploitation allows for arbitrary command execution on the underlying Linux operating system. A public exploit (PoC) has been released.

Affected products

Totolink A8000RU 7.1cu.643_b20200521

Timeline

2026-05-24: disclosed: Vulnerability details and PoC published by researcher.
2026-05-24: advisory: CVE-2026-9387 published.

References

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