Authentication Bypass in QNAP TS-453E (CVE-2025-62847) Enables Unauthenticated Access – Moderate Risk for TPRM

Authentication Bypass in QNAP TS-453E (CVE-2025-62847) – Moderate Risk for TPRM

What It Is – A medium‑severity (CVSS 6.3) authentication‑bypass flaw in the SMB daemon of QNAP’s TS‑453E NAS appliance. The vulnerability stems from improper validation of the domain_name argument, allowing an attacker to craft a malicious request that skips login entirely.

Exploitability – The flaw is network‑adjacent, requires no credentials, and has been publicly disclosed with a vendor‑issued patch. No public PoC or active exploit‑as‑a‑service has been observed, but the attack surface is trivial for any host that can reach the device’s SMB port.

Affected Products – QNAP TS‑453E (all firmware versions prior to the March 2026 security update).

TPRM Impact – QNAP NAS units are widely deployed as third‑party storage for backups, file sharing, and archival across many industries. An unauthenticated bypass could let a supply‑chain partner—or a compromised network segment—access sensitive corporate data, inject malicious files, or pivot to other internal systems.

Recommended Actions –

• Deploy QNAP’s March 2026 firmware update (QSA‑25‑45) immediately.
• If SMB is not required, disable the service or restrict it to trusted VLANs/IP ranges.
• Enforce network segmentation: place NAS devices behind firewalls and monitor SMB traffic for anomalous domain_name strings.
• Conduct a rapid audit of any data stored on TS‑453E units for signs of unauthorized access.
• Update third‑party risk registers to reflect the new vulnerability and verify that all vendors using QNAP NAS have applied the patch.

Source: Zero Day Initiative Advisory – ZDI‑26‑216