CVE-2026-6643

CRITICAL

ASUSTOR ADM 4.1.0-4.3.3.RR42 and 5.0.0-5.1.2.REO1 - Authenticated Remote Code Execution via VPN Client Buffer Overflow

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-6643. PoCs published by mlgzackfly.

AI-analyzed exploit summary This repository contains a functional exploit for CVE-2026-6643, targeting ASUSTOR ADM 5.1.2. The exploit leverages a format string vulnerability (CWE-134) and a stack buffer overflow (CWE-121) in the `vpnupload.cgi` component to achieve remote code execution (RCE). The exploit is well-documented with detailed technical analysis, including stack layout, mitigation bypasses, and step-by-step exploitation instructions.

Description

A stack-based buffer overflow vulnerability was found in the VPN Clients on the ADM. The issue stems from the use of unbounded sscanf() and passing user-controlled data directly to printf(). Due to the lack of PIE and Stack Canary protections, an authenticated remote attacker can exploit these to execute arbitrary code as the web server user. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.RR42 as well as from ADM 5.0.0 through ADM 5.1.2.REO1.

Exploits (1)

github WORKING POC
by mlgzackfly · pythonpoc
https://github.com/mlgzackfly/CVE-2026-6643

This repository contains a functional exploit for CVE-2026-6643, targeting ASUSTOR ADM 5.1.2. The exploit leverages a format string vulnerability (CWE-134) and a stack buffer overflow (CWE-121) in the `vpnupload.cgi` component to achieve remote code execution (RCE). The exploit is well-documented with detailed technical analysis, including stack layout, mitigation bypasses, and step-by-step exploitation instructions.

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Complex
Reliability
Reliable
Target: ASUSTOR ADM 5.1.2.REO1 (X64_G3)
Auth required
Prerequisites: Valid `Revive_Session` cookie · Access to `/portal/apis/settings/vpnupload.cgi`
devstral-2 · analyzed Apr 28, 2026 Full analysis →

References (1)

Core 1
Core References

Scores

CVSS v3 9.9
EPSS 0.0047
EPSS Percentile 36.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-121
Status published
Products (3)
asustor/data_master 4.1.0.rhu2 - 4.3.3.RR42
ASUSTOR Inc./ADM 4.1.0 - 4.3.3.RR42
ASUSTOR Inc./ADM 5.0.0 - 5.1.2.REO1
Published Apr 20, 2026
Tracked Since Apr 20, 2026