Is CVE-2026-9435 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-9435 being exploited in the wild.

How severe is CVE-2026-9435?

Critical severity, with a CVSS score of 9.8, published 25 May 2026.

Which products and versions are affected?

TOTOLINK A8000RU 7.1cu.643_b20200521.

Is there a fix for CVE-2026-9435?

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-2026-9435 attacked?

It is attacked over the network, in device firmware.

Am I affected by CVE-2026-9435?

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-2026-9435: Totolink A8000RU command injection in setQosCfg

CVE-2026-9435 · Severity: critical · CVSS 9.8 · Published 2026-05-25

A vulnerability exists in the Totolink A8000RU router, a device used to provide wireless internet connectivity. 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 person 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-2026-9435 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-9435 being exploited in the wild.
How severe is CVE-2026-9435?: Critical severity, with a CVSS score of 9.8, published 25 May 2026.
Which products and versions are affected?: TOTOLINK A8000RU 7.1cu.643_b20200521.
Is there a fix for CVE-2026-9435?: 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-2026-9435 attacked?: It is attacked over the network, in device firmware.
Am I affected by CVE-2026-9435?: 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 'setQosCfg' function within the '/cgi-bin/cstecgi.cgi' component of the Totolink A8000RU firmware (version 7.1cu.643_b20200521). The vulnerability is rooted in the improper sanitization of the 'enable' parameter. User-provided input is passed to 'snprintf' and subsequently executed via 'execv()' through the 'CsteSystem' function in 'libcscommon.so'. A remote, unauthenticated attacker can exploit this by sending a crafted POST request containing shell metacharacters (e.g., backticks) to execute arbitrary commands with elevated privileges. A public proof-of-concept (PoC) demonstrating file creation via command injection is available.

Affected products

Totolink A8000RU 7.1cu.643_b20200521

Timeline

2026-05-25: disclosed: Initial vulnerability disclosure and CVE assignment.
2026-05-25: advisory: NVD published the vulnerability details.

References

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