Quick answer
Direct answer
Risk scores
| CVSS metric | What it means |
|---|---|
| Attack vector (AV:N) | Network: reachable remotely |
| Attack complexity (AC:L) | Low complexity |
| Attack requirements (AT:N) | No attack requirements |
| Privileges required (PR:H) | High privileges required |
| User interaction (UI:N) | No user interaction |
| Confidentiality (VC:H) | High confidentiality impact |
| Integrity (VI:H) | High integrity impact |
| Availability (VA:H) | High availability impact |
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
About Asustor Data Master
CVE-2026-6644 affects Asustor Data Master, a product from Asustor. Before acting, confirm where Asustor Data Master runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.
What the flaw is
In plain terms: A command injection vulnerability was found in the PPTP VPN Clients on the ADM. The vulnerability allows an administrative user to break out of the restricted web environment and execute arbitrary code on the underlying operating system. This occurs due to insufficient validation of user-supplied input before it is passed to a system shell. Successful exploitation allows an attacker to achieve Remote Code Execution (RCE) and fully compromise the system. 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.
The weakness class is OS Command Injection. Untrusted input is passed to the operating system shell, letting an attacker run commands.
Based on its CVSS vector, the flaw can be reached over the network, needs some level of access, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Affected versions and timeline
| Field | Detail |
|---|---|
| Product | Asustor Data Master |
| Affected versions | Data Master from 4.1.0.rhu2 before 4.3.3.RR42; Data Master from 5.0.0.ra82 before 5.1.2.reo1 |
| Published | Apr 20, 2026 |
| Last modified | Jun 17, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | security@asustor.com |
How to detect it
- Inventory every instance of Asustor Data Master and record the running version against the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
- Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.
How to fix it
- Apply the fixed version of Asustor Data Master named in the vendor advisory.
- If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
- Rescan after the change to prove the exposure is gone, then close the ticket.
CTEM action plan
| CTEM stage | What to do for this CVE |
|---|---|
| Scope | Add every business service that depends on Asustor Data Master to the current CTEM cycle. |
| Discover | Find all instances, including shadow and cloud deployments, and record versions and exposure. |
| Prioritize | Rank using EPSS and CVSS together with asset exposure and business impact. |
| Validate | Confirm the flaw is reachable and exploitable in your environment and that compensating controls work. |
| Mobilize | Assign the fix to the asset owner with a due date matched to the priority, then verify closure. |
CWE References
- CWE-78: OS Command Injection More CVEs with this weakness
Technical References
Frequently asked questions
Related CVEs
A stack-based buffer overflow vulnerability was found in the File Explorer on the ADM. The vulnerability occurs because user-controlled input is not properly validated before being decoded and copied into a fixed-size stack buffer. An authenticated attacker can exploit this issue to cause denial of service of the affected CGI process. Further impact may be possible depending on exploitability and runtime protections. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.RUN1 as well as from ADM 5.0.0 through ADM 5.1.3.RI81.
A path traversal vulnerability was found in the VPN Clients on the ADM. The vulnerability occurs because user-controlled certificate name input is not sufficiently validated before being used to construct the upload destination path. An authenticated attacker can exploit this issue to write an uploaded certificate file outside the intended VPN certificate directory, subject to process privileges and filesystem permissions. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.RUN1 as well as from ADM 5.0.0 through ADM 5.1.3.RI81.
A format string vulnerability was found in the Notification OAuth settings of ADM. The vulnerability occurs because user-controlled notification configuration input may be processed through an unsafe format string operation. An authenticated administrator can exploit this issue to disclose memory information or cause denial of service of the affected component. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.RUN1 as well as from ADM 5.0.0 through ADM 5.1.3.RI81.
A format string vulnerability was found in the Rsync Backup on the ADM. The vulnerability occurs because user-controlled rsync backup configuration or log data may be processed through an unsafe format string operation. An authenticated attacker can exploit this issue to disclose memory information or cause denial of service of the affected backup component. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.RUN1 as well as from ADM 5.0.0 through ADM 5.1.3.RI81.
A format string vulnerability was found in the Internal Backup on the ADM. The vulnerability occurs because user-controlled task input may be included in an error response and processed through an unsafe format string operation. An authenticated attacker can exploit this issue to disclose memory information or cause denial of service of the affected CGI process. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.RUN1 as well as from ADM 5.0.0 through ADM 5.1.3.RI81.
A stored format string vulnerability was found in the FTP Backup on the ADM. The vulnerability occurs because user-controlled backup configuration data may be written into a task log and later processed through an unsafe format string operation. An authenticated attacker can exploit this issue to disclose memory information or cause denial of service of the affected CGI process. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.RUN1 as well as from ADM 5.0.0 through ADM 5.1.3.RI81.
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