---
id: "CVE-2026-123958"
page: "https://infrastack.ai/live/CVE-2026-123958"
kind: "vulnerability"
aliases: ["CVE-2026-123958"]
title: "TOTOLINK CA300-PoE router: setLanConfig buffer overflow allows remote attack"
severity: "critical"
cvss: 9.9
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "CA300-PoE", "fixed": [], "affected": "6.2c.884", "ecosystem": "firmware"}]
ecosystems: []
tags: ["buffer-overflow", "ca300-poe", "embedded", "firmware", "infrastructure", "router", "totolink"]
not_affected_if: ["management-not-exposed", "other-firmware-versions"]
published_at: "2026-11-07T09:17:15+00:00"
first_seen_at: "2026-11-07T09:46:25+00:00"
updated_at: "2026-11-07T09:48:47+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123958", "first_seen_at": "2026-11-07T09:46:25+00:00"}, {"source": "analyst", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123958", "first_seen_at": "2026-11-07T09:48:47+00:00", "cites": ["https://nvd.nist.gov/vuln/detail/CVE-2026-123958", "https://securityonline.info/cve-watchtower/cve-2026-123958/"]}]
exploit_sources: []
---

# TOTOLINK CA300-PoE router: setLanConfig buffer overflow allows remote attack

Link for people: https://infrastack.ai/live/CVE-2026-123958 (this .md is for agents)

The TOTOLINK CA300-PoE 6.2c.884 web management interface mishandles the lanDns, lanSecDns and langType arguments of setLanConfig in /cgi-bin/cstecgi.cgi, causing a buffer overflow. A remote attacker can exploit this, and a public exploit is said to exist, which could lead to code execution on the device.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- firmware:CA300-PoE affected 6.2c.884 fixed no fixed version listed

## How to check

- Check whether the device is a TOTOLINK CA300-PoE running firmware 6.2c.884 (admin web interface, device info page)
- Check whether the web management interface (/cgi-bin/cstecgi.cgi) is reachable from the internet or untrusted networks; the CVSS vector says low privileges are required, so a login may be needed
- Also check any other TOTOLINK firmware you run: earlier CA300-PoE CVEs share the same cstecgi.cgi code, but no source confirms them here

## Timeline

- 2026-11-07T09:46:25+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123958
- 2026-11-07T09:48:47+00:00 analyst https://nvd.nist.gov/vuln/detail/CVE-2026-123958 — NVD record and mirrors only; no TOTOLINK advisory or fixed firmware found (vendor download page lists no fix). Affected: 6.2c.884 only per NVD. Public exploit said to exist but no link found, no exploitation confirmed. Nothing verified. Sibling CVE-2026-123957 same product.

## Documents

- [describes] NVD: CVE-2026-123958 https://nvd.nist.gov/vuln/detail/CVE-2026-123958
- [mentions] CVE Watchtower: CVE-2026-123958 https://securityonline.info/cve-watchtower/cve-2026-123958/

## From the sources

A vulnerability was identified in TOTOLINK CA300-PoE 6.2c.884. The affected element is the function setLanConfig of the file /cgi-bin/cstecgi.cgi. Such manipulation of the argument lanDns/lanSecDns/langType leads to buffer overflow. It is possible to launch the attack remotely. The exploit is publicly available and might be used.

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_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_