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Data MasterOperating system · Asustor

CVE-2026-3100

MEDIUM · 6.5 CVSS v3.1 Published 2026-02-25
Fix available
A fix is available. Upgrade to 5.1.2.reo1 or later.
See remediation →
74/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The FTP Backup on the ADM will not properly strictly enforce TLS certificate verification while connecting to an FTP server using FTPES/FTPS. An improper validated TLS/SSL certificates allows a remote attacker can intercept network traffic to perform a Man-in-the-Middle (MitM) attack, which may intercept, modify, or obtain sensitive information such as authentication credentials and backup data. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.ROF1 as well as from ADM 5.0.0 through ADM 5.1.2.RE51.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The FTP Backup feature in Asustor ADM fails to properly enforce TLS certificate validation when connecting to FTP servers via FTPES/FTPS protocols. This allows a remote attacker positioned on the network to perform a Man-in-the-Middle attack, intercepting and potentially modifying sensitive data including authentication credentials and backup contents.

MitigationApply vendor patches when available. Until then, avoid transmitting sensitive backup data over untrusted networks or consider alternative secure transfer methods with proper certificate verification.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Data MasterOperating system
Affected:>= 4.1.0.rhu2, <= 4.3.3.rof1>= 5.0.0.ra82, < 5.1.2.reo1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check ADM version
    Log into the ADM web interface and navigate to Settings > System > Version Info to view the installed ADM version number.
    Affected if The installed version falls within 4.1.0.rhu2 through 4.3.3.rof1 OR 5.0.0.ra82 through 5.1.2.reo0 (versions before 5.1.2.reo1).
  2. Verify FTP Backup feature is configured
    Navigate to Backup & Restore > FTP Backup in the ADM interface. Check if any FTP backup jobs are created and enabled.
    Affected if FTP Backup jobs are configured and active, making the system a potential target.
  3. Inspect FTP backup protocol settings
    In the FTP Backup configuration panel for each job, examine the server connection settings to determine if FTPES (Explicit FTP over TLS) or FTPS (Implicit FTP over TLS) is selected.
    Affected if FTPES or FTPS protocol is selected, as these are the protocols where certificate validation is not enforced.
  4. Check backup destination accessibility
    Review the FTP server hostname/IP address configured in each backup job. Determine if the destination server is on an untrusted or public network.
    Affected if Backup jobs connect to FTP servers accessible over untrusted networks, exposing the MITM attack vector.

A user is affected if running a vulnerable ADM version (4.1.0.rhu2-4.3.3.rof1 or 5.0.0.ra82-5.1.2.reo0) AND has FTP backup jobs configured using FTPES/FTPS to accessible destinations.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.1.2.reo1 or later
Fixed in 5.1.2.reo1
Interim mitigation

Apply vendor patches when available. Until then, avoid transmitting sensitive backup data over untrusted networks or consider alternative secure transfer methods with proper certificate verification.

Recommended fix Moderate confidence

ADM 5.1.2.REO1 or later (for ADM 5.x branch); ADM 5.x recommended for 4.x branch users

  1. 1. Identify the current ADM version installed on the ASUSTOR NAS device.
  2. 2. For ADM 5.x versions: Upgrade to ADM version 5.1.2.REO1 or later, which contains the fix for proper TLS certificate validation in FTP Backup.
  3. 3. For ADM 4.x versions: No specific fixed version is documented in the available reference material; consider upgrading to a newer ADM 5.x release (5.1.2.REO1 or later) if the 4.x branch is no longer supported.
  4. 4. After upgrading, verify that FTP Backup with FTPES/FTPS now properly validates TLS certificates.
  5. 5. Test the FTP Backup functionality to ensure the fix does not disrupt legitimate backup operations.
Caveat Upgrading ADM major versions (e.g., 4.x to 5.x) may introduce interface changes or require reconfiguration of some applications; review ASUSTOR migration notes before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Data Master Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-3100 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data