CVE-2026-3100
Published: 25 February 2026
Summary
CVE-2026-3100 is a high-severity Improper Certificate Validation (CWE-295) vulnerability in Asustor Data Master. Its CVSS base score is 8.3 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Adversary-in-the-Middle (T1557); ranked at the 7.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-8516
Vulnerability details
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)…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Improper TLS certificate validation (CWE-295) in FTPS/FTPES backup connections directly enables MitM attacks for traffic interception and credential/data theft.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
When certificates are used to establish component provenance, the control requires correct certificate validation procedures.
Mandates approved trust anchors and issuance policies, directly preventing acceptance of unvalidated or untrusted certificates.
Correct system time is required for proper enforcement of certificate notBefore/notAfter dates and time-based revocation checks.