Which products and versions are affected by CVE-2020-2509?

Affected: QTS (Qnap) versions 4.2.6, 4.2.6-build_20170517, 4.2.6-build_20190322, 4.2.6-build_20190730, 4.2.6-build_20190921, 4.2.6-build_20191107, 4.2.6-build_20200109, 4.2.6-build_20200421; QuTS hero (Qnap) versions h4.5.1, h4.5.1.1472, >= unspecified. The full list is in the CVE brief.

Is CVE-2020-2509 being exploited in the wild?

It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Apr 11, 2022 and is known to be used in ransomware campaigns.

Is CVE-2020-2509 in the CISA KEV catalog?

Yes. It was added on Apr 11, 2022 with a federal remediation due date of May 2, 2022.

Is there a public exploit for CVE-2020-2509?

Public exploit code is available.

Is there a fix for CVE-2020-2509?

Fixed versions are available, including QTS 4.2.6, QTS 4.2.6 Build 20210327, QTS 4.3.3.1624 Build 20210416.

How urgently should CVE-2020-2509 be patched?

Brandefense priority: patch immediately, because it is listed as exploited in the wild.

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Vulnerability Intelligence

CVE-2020-2509

CriticalExploitedPublic exploit

A command injection vulnerability has been reported to affect QTS and QuTS hero.

Published Apr 5, 2021 · Updated Oct 21, 2025 · Also known as TR-21-0282

Key Facts

Patch immediately

CVE-2020-2509 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting QTS (Qnap), QuTS hero (Qnap).
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Apr 11, 2022 and is known to be used in ransomware campaigns. Public exploit code is available.
EPSS estimates a 34% probability of exploitation in the next 30 days.
Fixed versions are available, including QTS 4.2.6, QTS 4.2.6 Build 20210327, QTS 4.3.3.1624 Build 20210416.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v3.1

9.8

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

EPSS (30-day exploit likelihood)

34%

Higher than 98.3% of all scored CVEs

Exploited in the wild

Yes

4 catalog listings, used by ransomware

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2020-2509 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

A command injection vulnerability has been reported to affect QTS and QuTS hero. If exploited, this vulnerability allows attackers to execute arbitrary commands in a compromised application. We have already fixed this vulnerability in the following versions: QTS 4.5.2.1566 Build 20210202 and later QTS 4.5.1.1495 Build 20201123 and later QTS 4.3.6.1620 Build 20210322 and later QTS 4.3.4.1632 Build 20210324 and later QTS 4.3.3.1624 Build 20210416 and later QTS 4.2.6 Build 20210327 and later QuTS hero h4.5.1.1491 build 20201119 and later

Known-Exploited Catalog Listings

Catalog	Added	Remediation due	Ransomware use
CISA KEV	Apr 11, 2022	May 2, 2022	Not reported
Industry KEV feed	Apr 11, 2022	May 2, 2022	Known
CIRCL KEV	Apr 11, 2022	May 2, 2022	Not reported
ENISA EUVD	Apr 11, 2022	n/a	Not reported

Required action: Apply updates per vendor instructions.

Affected Products

86 affected entries in total

Product	Affected versions	Fixed in
QTSQnap	4.2.6, 4.2.6-build_20170517, 4.2.6-build_20190322, 4.2.6-build_20190730, 4.2.6-build_20190921, 4.2.6-build_20191107, 4.2.6-build_20200109, 4.2.6-build_20200421	4.2.6
QuTS heroQnap	h4.5.1, h4.5.1.1472, >= unspecified	h4.5.1

Patched Releases

QTS

4.2.6, 4.2.6 Build 20210327, 4.3.3.1624 Build 20210416, 4.3.4.1632 Build 20210324, 4.3.6.1620 Build 20210322, 4.5.1.1495 Build 20201123, 4.5.2.1566 Build 20210202

QuTS hero

h4.5.1, h4.5.1.1491 build 20201119

Timeline

Publicly disclosed
Apr 5, 2021
Added to CISA KEV
Apr 11, 2022
Added to Industry KEV feed
Apr 11, 2022
Added to CIRCL KEV
Apr 11, 2022
Added to ENISA EUVD
Apr 11, 2022
Last updated
Oct 21, 2025

Weakness Type

CWE-77 Improper Neutralization of Special Elements used in a Command ('Command Injection')
CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

References

advisoryhttps://www.cybersecurity-help.cz/vdb/SB2021040201
advisoryhttps://www.qnap.com/en/security-advisory/qsa-21-05
advisoryUSOM advisory
exploitVulnCheck exploitation report
exploitVulnCheck exploitation report

3 more references in the full CVE brief

FAQ

Common Questions.

A command injection vulnerability has been reported to affect QTS and QuTS hero.
Affected: QTS (Qnap) versions 4.2.6, 4.2.6-build_20170517, 4.2.6-build_20190322, 4.2.6-build_20190730, 4.2.6-build_20190921, 4.2.6-build_20191107, 4.2.6-build_20200109, 4.2.6-build_20200421; QuTS hero (Qnap) versions h4.5.1, h4.5.1.1472, >= unspecified. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Apr 11, 2022 and is known to be used in ransomware campaigns.
Yes. It was added on Apr 11, 2022 with a federal remediation due date of May 2, 2022.
Public exploit code is available.
Fixed versions are available, including QTS 4.2.6, QTS 4.2.6 Build 20210327, QTS 4.3.3.1624 Build 20210416.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

Is CVE-2020-2509 Running On Your Attack Surface?

Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.