---
id: "CVE-2026-10139"
kind: "vulnerability"
aliases: ["CVE-2026-10139"]
title: "TOTOLINK X2000R router: stack overflow in Mcli lets an attacker run code"
severity: "critical"
cvss: 9.1
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "TOTOLINK X2000R", "fixed": [], "affected": "TOTOLINK-X2000R-Gh-V1.0.0-B20250421.1327", "ecosystem": "firmware"}]
ecosystems: []
tags: ["infrastructure", "routers", "self-hosted", "totolink", "x2000r"]
not_affected_if: ["auth-required", "no-wan-admin"]
published_at: "2026-10-20T21:17:16+00:00"
first_seen_at: "2026-10-23T21:57:21+00:00"
updated_at: "2026-10-23T23:16:54+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-10139", "first_seen_at": "2026-10-23T21:57:21+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-23T23:16:54+00:00"}]
---

# TOTOLINK X2000R router: stack overflow in Mcli lets an attacker run code

Authenticated stack overflow in the Mcli helper binary of TOTOLINK X2000R firmware B20250421.1327. In formUpload, attacker-supplied devicemac%d POST parameters (mesh upgrade mode) are put into a system() command line for Mcli, which strcpy's them into 0x12-byte stack buffers. An admin-level session can get code execution as root. CVSS 9.1 (Talos), PR:H.

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

## Affected

- firmware:TOTOLINK X2000R affected TOTOLINK-X2000R-Gh-V1.0.0-B20250421.1327 fixed ?

## How to check

Open the router admin page (Status/System info) and read the firmware version. TOTOLINK-X2000R-Gh-V1.0.0-B20250421.1327 is confirmed vulnerable. Also check whether the admin web UI (port 80/boa) is reachable from WAN or untrusted LAN/guest networks.

## Fix

No fixed firmware published in the sources; unknown. Check totolink.net X2000R product page for newer firmware. Until then: disable WAN/remote management, use a strong unique admin password, keep the admin UI off guest and IoT networks.

## Timeline

- 2026-10-23T21:57:21+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-10139
- 2026-10-23T23:16:54+00:00 analyst — Read Talos TALOS-2026-2439 (primary, truncated before vendor timeline) and NVD. Authenticated (PR:H) only; no fixed firmware named anywhere; no X posts; no public exploit or exploitation seen. Sibling X2000R CVEs share the same firmware.

## Documents

- [advisory] TALOS-2026-2439 Totolink X2000R Mcli stack-based buffer overflow https://talosintelligence.com/vulnerability_reports/TALOS-2026-2439
- [describes] NVD CVE-2026-10139 https://nvd.nist.gov/vuln/detail/CVE-2026-10139

## From the sources

A stack-based buffer overflow vulnerability exists in the Mcli functionality of X2000R (version(s): TOTOLINK-X2000R-Gh-V1.0.0-B20250421.1327). A specially crafted HTTP request can lead to arbitrary code execution. An attacker can make an authenticated HTTP request to trigger this vulnerability.

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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_