CVE-2021-34345Network attack vector

Unauthenticated arbitrary code execution

Published Sep 10, 2021 · Updated Sep 16, 2024

A stack buffer overflow in QNAP NVR Storage Expansion before 1.0.6 allows remote attackers to execute arbitrary code over the network. QNAP has not published the affected component, the input reaching it, or the operation that overruns the stack buffer. No authentication or user interaction is required, and successful exploitation permits attacker-controlled code to run on the NAS.

CVSS severity9.8
Critical
EPSS probability1.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

A stack buffer overflow in QNAP NVR Storage Expansion before 1.0.6 allows remote attackers to execute arbitrary code over the network. QNAP has not published the affected component, the input reaching it, or the operation that overruns the stack buffer. No authentication or user interaction is required, and successful exploitation permits attacker-controlled code to run on the NAS.

The record

CVE
CVE-2021-34345
Published
Sep 10, 2021
Updated
Sep 16, 2024
Vendor
Linn Products Limited
Product
NVR Storage Expansion
Classifications
CWE-787, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 10, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=unspecified <1.0.6 ( 2021/08/03 )

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Linn Products Limited · NVR Storage Expansionversion=unspecified <1.0.6 ( 2021/08/03 )

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8QNAP Systems, Inc.CVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo