CVE-2018-19943: QNAP NAS File Station Cross-Site Scripting Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 24 May 2022, 573 days after the CVE record was published.

How likely is exploitation in the next 30 days?

22.7%

EPSS score, percentile 97.7 of all scored records

How severe?

8.0 High

CVSS v3.1 base score, given by the CNA

What should I do?

CISA deadline 14 Jun 2022. Apply updates per vendor instructions.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

• before 4.4.2.1270
• before 4.4.1.1261
• before 4.3.6.1263
• before 4.3.4.1282
• before 4.3.3.1252
• before 4.2.6

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

CISA due date for this action: 14 June 2022.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

• https://nvd.nist.gov/vuln/detail/CVE-2018-19943

Affected products and versions

As listed in the CVE record.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

A cross-site scripting vulnerability affecting QNAP NAS File Station could allow remote attackers to inject malicious code.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

• CISA added CVE-2018-19943 to its Known Exploited Vulnerabilities (KEV) catalog on 24 May 2022.
• CISA marks it as known to be used in ransomware campaigns.
• The due date CISA sets for the required action is 14 Jun 2022.
• The CVE record was published on 28 Oct 2020, 573 days before it was added to KEV.
• The CVE record carries a CVSS v3.1 base score of 8.0 (High), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 22.7% (percentile 97.7), as of 28 Oct 2026.
• CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

If exploited, this cross-site scripting vulnerability could allow remote attackers to inject malicious code. QNAP has already fixed these issues in the following QTS versions. QTS 4.4.2.1270 build 20200410 and later QTS 4.4.1.1261 build 20200330 and later QTS 4.3.6.1263 build 20200330 and later QTS 4.3.4.1282 build 20200408 and later QTS 4.3.3.1252 build 20200409 and later QTS 4.2.6 build 20200421 and later

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

• CWE-79: Cross-site Scripting (XSS)
• CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

References

• qnap.com

More exploited QNAP vulnerabilities

• CVE-2023-47565: QNAP VioStor NVR OS Command Injection Vulnerability (added 21 Dec 2023)
• CVE-2022-27593: QNAP Photo Station Externally Controlled Reference Vulnerability (added 8 Sep 2022)
• CVE-2019-7192: QNAP Photo Station Improper Access Control Vulnerability (added 8 Jun 2022)
• CVE-2019-7193: QNAP QTS Improper Input Validation Vulnerability (added 8 Jun 2022)
• CVE-2019-7194: QNAP Photo Station Path Traversal Vulnerability (added 8 Jun 2022)
• CVE-2019-7195: QNAP Photo Station Path Traversal Vulnerability (added 8 Jun 2022)