Medium 6.1Known exploited (CISA KEV)Published Oct 28, 2020

CVE-2018-19953If exploited, this cross-site scripting vulnerability could allow remote attackers to inject malicious code.

Updated under an hour ago (2026-10-19 08:40 UTC)

Does this affect you?

It affects QNAP Systems Inc. QTS and 1 other product. Add what you run to find out whether that includes you.

CISA lists it as known exploited since May 24, 2022; federal agencies had to remediate by Jun 14, 2022, and it is known to be used in ransomware. Treat that date as your deadline.

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Every CVE for QNAP Systems Inc. QTS

Exploited in the last 30 days

If exploited, this cross-site scripting vulnerability could allow remote attackers to inject malicious code. QNAP has already fixed the issue in the following QTS versions. QTS 4.4.2.1231 on build 20200302; QTS 4.4.1.1201 on build 20200130; QTS 4.3.6.1218 on build 20200214; QTS 4.3.4.1190 on build 20200107; QTS 4.3.3.1161 on build 20200109; QTS 4.2.6 on build 20200109.

CVSS: 6.1 MEDIUM (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE): CWE-79, CWE-80
Known exploited: Added to CISA KEV May 24, 2022; federal remediation due Jun 14, 2022; known ransomware useApply updates per vendor instructions.
EPSS (exploitation in the next 30 days): 28.98% (percentile 98)
Assigned by: qnap
NVD analysis: Analyzed
Record last updated: Oct 1, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

QNAP Systems Inc. QTS qnap_systems:qts (from the name)	from unspecified before 4.4.2.1231	CNA record
qnap qts qnap:qts	before 4.2.6; from 4.3.1.0013 before 4.3.3.1161; from 4.3.4 before 4.3.4.1190; from 4.3.6 before 4.3.6.1218; from 4.4.0 before 4.4.1.1201; from 4.4.2 before 4.4.2.1231; 4.2.6; 4.2.6; and 4 more ranges	NVD

References

https://www.qnap.com/zh-tw/security-advisory/qsa-20-01x-refsource-misc, vendor-advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-19953us-government-resource

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.