CVE-2026-51677
Unauthenticated UPnP control in TOTOLINK T6 allows attackers to change UPnP state.
Is CVE-2026-51677 being exploited?
Not confirmed. CVE-2026-51677 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-2026-51677?
CVE-2026-51677 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-2026-51677?
Not known from our data. No patch reference has been recorded for CVE-2026-51677, 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-2026-51677 affect?
CVE-2026-51677 affects TOTOLINK T6 (firmware 4.1.5cu.748_B20211015), Devices exposing /cgi-bin/cstecgi.cgi setUPnPCfg. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-51677?
Block WAN access to router admin and /cgi-bin/cstecgi.cgi, disable UPnP, apply vendor firmware when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated attacker can toggle UPnP via crafted POST, enabling port mappings that expose internal hosts and enable remote access to LAN services.
Immediate action required