CVE-2018-19943
QNAP NAS (QTS / QuTS hero) · Backup, storage and NAS
QNAP NAS File Station Cross-Site Scripting Vulnerability
At a glance
Exploited. Added to CISA’s catalog of exploited vulnerabilities on May 24, 2022.
Used in ransomware attacks, according to CISA.
Affected product: QNAP NAS (QTS / QuTS hero) (category Backup, storage and NAS, indicative classification). Name in CISA’s catalog: QNAP Network Attached Storage (NAS).
What should I do?
Apply the security update from QNAP.
Deadline set by CISA for US federal agencies: 21 days (due June 14, 2022). It only binds those agencies, but it is a useful measure of urgency.
- QNAP security advisories page (general page, not the advisory for this vulnerability)
- The vendor’s specific advisory is listed in the NVD references: CVE-2018-19943 on the NVD website.
Original text of the required action (CISA)
Apply updates per vendor instructions.
Timeline
- Vulnerability published Publication date (NVD)
- Exploitation confirmed Added to CISA’s KEV catalog
- CISA deadline Remediation deadline set for US federal agencies
The facts, with their sources
- Exploitation confirmed
- Yes, on May 24, 2022 Date added to the catalog of exploited vulnerabilities. Exploitation itself may have started earlier. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- Ransomware
- Known use Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- Hunt for compromise
- Not requested by CISA Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- CISA required action
- Apply the security update from QNAP. Rewritten by this site from CISA’s original text. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- CISA deadline
- June 14, 2022, 21 days Set for US federal agencies: a measure of urgency, not an obligation elsewhere. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- Vulnerability published
- October 28, 2020 Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
- Product according to CISA
- QNAP Network Attached Storage (NAS) Filed by this site under “Backup, storage and NAS” (indicative classification). Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Technical detail of the score: attack vector, complexity, impact. Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
Severity and activity
FIRST’s EPSS model. Since exploitation is already confirmed, this figure is mostly useful to compare activity. Collected Sep 29, 2026.
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
Official description from the NVD, collected Sep 29, 2026. CVE® description © The MITRE Corporation.
A cross-site scripting vulnerability affecting QNAP NAS File Station could allow remote attackers to inject malicious code.
Summary from CISA (KEV catalog).
CERT-FR advisories
No advisory among the latest CERT-FR publications this site follows. That does not mean there are none.
Information reused under the Open Licence 2.0 (Etalab); the date of last update is shown for each advisory. This site is neither affiliated with nor endorsed by ANSSI.
Sources for this page
- CISA KEV catalog: exploitation, date added, required action, deadline, ransomware.
- NVD (NIST): CVSS severity, publication date, description, vendor references.
- EPSS (FIRST): probability of exploitation.
- CERT-FR: advisories and alerts (in French).
- Brand and category: indicative classification by this site (method).