---
id: "CVE-2026-121597"
kind: "vulnerability"
aliases: ["CVE-2026-121597"]
title: "TOTOLINK A950RG router: stack overflow in setup wizard lets remote attackers in"
severity: "critical"
cvss: 9.9
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "A950RG firmware", "fixed": [], "affected": "4.1.2cu.5268_B20221104", "ecosystem": "vendor"}]
ecosystems: []
tags: ["a950rg", "firmware", "infrastructure", "iot", "routers", "totolink"]
not_affected_if: ["admin-interface-lan-only", "other-firmware-version"]
published_at: "2026-11-04T00:17:27+00:00"
first_seen_at: "2026-11-04T00:46:18+00:00"
updated_at: "2026-11-04T00:50:33+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121597", "first_seen_at": "2026-11-04T00:46:18+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-11-04T00:50:33+00:00"}]
---

# TOTOLINK A950RG router: stack overflow in setup wizard lets remote attackers in

The TOTOLINK A950RG router firmware has a stack-based buffer overflow in the Easy Setup Wizard handler, reached through the functionType argument of setAppEasyWizardConfig in /cgi-bin/cstecgi.cgi. A remote attacker can send a crafted request to overwrite memory, which can lead to code execution on the device; a public exploit has been released.

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

## Affected

- vendor:A950RG firmware affected 4.1.2cu.5268_B20221104 fixed ?

## How to check

- Log in to the router admin page and read the firmware version under system status; the version named in the CVE is 4.1.2cu.5268_B20221104.
- Check whether the web management interface answers from the internet (WAN address, ports 80/443); if so, turn off remote management.
- Authentication requirement is not stated: the CVSS vector lists PR:L (low privileges), so assume a login may be needed but do not rely on it.
- No vendor patch page was found; check totolink.net downloads for the A950RG for newer firmware than 4.1.2cu.5268_B20221104.

## Timeline

- 2026-11-04T00:46:18+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121597
- 2026-11-04T00:50:33+00:00 analyst — Only NVD/VulDB-derived data found (CVSS 4.0 vector PR:L, public exploit per description). No TOTOLINK advisory or fixed firmware found, no PoC link found for this CVE, X not checked. Same firmware build has several other recent A950RG CVEs (e.g. CVE-2026-116504/116506/116508). Fix left unknown, nothing verified.

## Documents

- [describes] NVD CVE-2026-121597 https://nvd.nist.gov/vuln/detail/CVE-2026-121597

## From the sources

A weakness has been identified in TOTOLINK A950RG 4.1.2cu.5268_B20221104. This affects the function setAppEasyWizardConfig of the file /cgi-bin/cstecgi.cgi of the component Easy Setup Wizard Handler. Executing a manipulation of the argument functionType can lead to stack-based buffer overflow. The attack may be performed from remote. The exploit has been made available to the public and could be used for attacks.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_