# CVE-2026-6643

> Vulnerability · severity: **CRITICAL** (CVSS 9.9).

## 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.

## Key facts

- **CVE ID:** CVE-2026-6643
- **Published:** 2026-04-20
- **CVSS severity:** CRITICAL
- **CVSS base score:** 9.9
- **CWE codes:** CWE-121

## Affected products

- `asustor:data_master`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6643

## Citation

> AI Analytics. CVE-2026-6643. Retrieved 2026-08-10 from https://api.ai-analytics.org/cve/CVE-2026-6643. Derived from NIST NVD. Licensed CC0.

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