CVE-2026-51723
Unauthenticated install of custom CGI module on TOTOLINK T6 via /cgi-bin/cstecgi.cgi
Is CVE-2026-51723 being exploited?
Not confirmed. CVE-2026-51723 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.29% probability of exploitation in the next 30 days.
How severe is CVE-2026-51723?
CVE-2026-51723 is rated Critical with a CVSS score of 9.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-51723?
Not known from our data. No patch reference has been recorded for CVE-2026-51723, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-51723 affect?
CVE-2026-51723 affects TOTOLINK T6 (firmware 4.1.5cu.748_B20211015), TOTOLINK routers running vulnerable firmware. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-51723?
Isolate affected devices, block /cgi-bin/cstecgi.cgi, change admin credentials, apply vendor firmware when released
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated attacker can install a custom CGI module enabling remote code execution, persistent backdoor, and full device/network compromise.
Immediate action required