CVE-2026-51723 Missing authorization in n/a

Critical 9.1 Published Updated

Unauthenticated attackers can install custom CGI modules on TOTOLINK T6 routers via crafted POST requests, leading to potential code execution.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Over the internet
Victim action needed
Not needed
Fix
None listed

What is CVE-2026-51723?

CVE-2026-51723 is a critical missing authorization vulnerability in n/a, published on 31 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Incorrect access control in the UploadCustomModule function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to install a custom CGI module via sending a crafted POST request to /cgi-bin/cstecgi.cgi.

Weakness: CWE-284

Which versions are affected by CVE-2026-51723?

How do I fix CVE-2026-51723?

No fix has been published for CVE-2026-51723 yet. Limit exposure of the affected software until one is available.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-51723 being exploited?

There is no known exploitation of CVE-2026-51723 in the wild and no public exploit code.

Sources

Also known as GHSA-44cj-pjqf-756c.

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