CVE-2026-51770
Unauthenticated MQTT QoS injection in TOTOLINK T6 allowing attacker-controlled QoS forwarding.
Is CVE-2026-51770 being exploited?
Not confirmed. CVE-2026-51770 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 0.44% probability of exploitation in the next 30 days.
How severe is CVE-2026-51770?
CVE-2026-51770 is rated Critical with a CVSS score of 9.8. 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-2026-51770?
Not known from our data. No patch reference has been recorded for CVE-2026-51770, 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-2026-51770 affect?
CVE-2026-51770 affects TOTOLINK T6 4.1.5cu.748_B20211015, cs_broker component, TOTOLINK routers with vulnerable firmware. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-51770?
Isolate affected devices, block/limit MQTT/cs_broker access, apply vendor firmware when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated attacker can send crafted MQTT to cs_broker to push QoS settings, enabling traffic manipulation, DoS, or interception.
Immediate action required