Is CVE-2026-123959 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-123959 being exploited in the wild.

How severe is CVE-2026-123959?

Critical severity, with a CVSS score of 9.1, published 7 November 2026.

Is there a fix for CVE-2026-123959?

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-2026-123959 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-123959?

Check whether you run TOTOLINK CA300-PoE 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-2026-123959: TOTOLINK CA300-PoE buffer overflow in setLanguageCfg

CVE-2026-123959 · Severity: critical · CVSS 9.1 · Published 2026-11-07

TOTOLINK CA300-PoE is a network access control appliance. A buffer overflow vulnerability in the language configuration function allows a remote attacker to execute arbitrary code and gain full control of the device, potentially compromising all connected network traffic and devices.

Technologies: TOTOLINK CA300-PoE. Vendors: TOTOLINK.

Quick answers

Is CVE-2026-123959 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-123959 being exploited in the wild.
How severe is CVE-2026-123959?: Critical severity, with a CVSS score of 9.1, published 7 November 2026.
Which products and versions are affected?: TOTOLINK CA300-PoE 6.2c.884.
Is there a fix for CVE-2026-123959?: 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-2026-123959 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-123959?: Check whether you run TOTOLINK CA300-PoE 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

A buffer overflow vulnerability exists in the setLanguageCfg function of /cgi-bin/cstecgi.cgi on TOTOLINK CA300-PoE version 6.2c.884. The langType argument is not properly validated, allowing an attacker to trigger a buffer overflow via remote network access. Exploitation can result in arbitrary code execution with device privileges.

Affected products

TOTOLINK CA300-PoE 6.2c.884

Timeline

2026-11-07: disclosed

References

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