CVE-2023-40042Public exploitNetwork attack vector

Remote code execution via unchecked MQTT comment copy

Published Aug 8, 2023 · Updated Oct 10, 2024

Stack overflow in TOTOLINK T10 V2 Firmware 5.9c.5061_B20200511 allows remote attackers to execute code via setStaticDhcpConfig MQTT packets. The function passes the MQTT comment value to strcpy, which copies it into a stack buffer without checking its length. Network access to the router's MQTT service is sufficient; an oversized comment can overwrite the return address, causing a crash or arbitrary code execution.

CVSS severity9.8
Critical
EPSS probability1.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stack overflow in TOTOLINK T10 V2 Firmware 5.9c.5061_B20200511 allows remote attackers to execute code via setStaticDhcpConfig MQTT packets. The function passes the MQTT comment value to strcpy, which copies it into a stack buffer without checking its length. Network access to the router's MQTT service is sufficient; an oversized comment can overwrite the return address, causing a crash or arbitrary code execution.

The record

CVE
CVE-2023-40042
Published
Aug 8, 2023
Updated
Oct 10, 2024
Vendor
TOTOLINK
Product
TOTOLINK T10 V2 Firmware
Classifications
CWE-787, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 8, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 10, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.9c.5061_b20200511

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

TOTOLINK · TOTOLINK T10 V2 Firmwareversion=5.9c.5061_b20200511

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo