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VulnerabilityPublished Updated

CVE-2025-8170: TOTOLINK T6 · Buffer Overflow

Affects TOTOLINK T6Source CVE Database V5

0

Public exploit available · CVSS 8.7 High.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
1.2% chance of exploitation in 30 days – higher than 68% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Jul 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: evidence found.

    CVSS exploit maturity: proof of concept public

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

AI-suggested

Organizations should immediately verify if they are using the TOTOLINK T6 router with the affected firmware version 4.1.5cu.748_B20211015. Since no official patches or updates are currently linked, users should: 1) Disable or restrict MQTT services if not required, especially blocking access to the tcpcheck_net function or related ports at the network perimeter. 2) Implement network segmentation to isolate vulnerable routers from critical internal systems. 3) Employ intrusion detection and prevention systems (IDS/IPS) with signatures that detect attempts to exploit this buffer overflow. 4) Monitor network traffic for unusual MQTT packet activity or malformed serverIp arguments. 5) Contact TOTOLINK support for firmware updates or advisories and apply patches promptly once available. 6) Consider replacing vulnerable devices with models from vendors with active security support if patches are delayed. 7) Educate IT staff about this vulnerability to ensure rapid incident response if exploitation is detected.

Description

A vulnerability classified as critical was found in TOTOLINK T6 4.1.5cu.748_B20211015. This vulnerability affects the function tcpcheck_net of the file /router/meshSlaveDlfw of the component MQTT Packet Handler. The manipulation of the argument serverIp leads to buffer overflow. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used.

References

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