CVE-2025-66276Network attack vector

Unauthorized NFS access via permissive export settings

Published Jun 10, 2026 · Updated Jun 10, 2026

Improper NFS access control in QNAP QTS 5.2.0 before 5.2.7.3256 build 20250913 allows remote attackers to access shared folders. Affected NFS host-access entries accept broad host scopes and preserve client identities when users are not squashed, exposing exports to unauthorized clients. The NFS service must be enabled and a shared folder must use permissive Host / IP / Network and Squash Option values; successful access permits file actions with the client's effective privileges.

CVSS severity9.2
Critical
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper NFS access control in QNAP QTS 5.2.0 before 5.2.7.3256 build 20250913 allows remote attackers to access shared folders. Affected NFS host-access entries accept broad host scopes and preserve client identities when users are not squashed, exposing exports to unauthorized clients. The NFS service must be enabled and a shared folder must use permissive Host / IP / Network and Squash Option values; successful access permits file actions with the client's effective privileges.

The record

CVE
CVE-2025-66276
Published
Jun 10, 2026
Updated
Jun 10, 2026
Vendor
Linn Products Limited
Product
QTS
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.2.0 <5.2.7.3256 build 20250913

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Linn Products Limited · QTSversion=5.2.0 <5.2.7.3256 build 20250913

Published CVSS scores

9.2QNAP Systems, Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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