CVE-2018-19943

Exp

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

Published: 2020-10-28 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-19943 is rated Critical Active Threat (95.9/100): CVSS High severity, with high exploitation likelihood (EPSS 17.71%, 97th percentile). CISA KEV confirms active exploitation (added 2022-05-24) affecting QNAP / Network Attached Storage (NAS). cross-site scripting (CWE-79) Unauthenticated remote administrative access may be possible. EPSS rose +10.67% over the last day, indicating growing attacker interest. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2018-19943

Name: QNAP NAS File Station Cross-Site Scripting Vulnerability · CISA KEV detail

Exploit added: 2022-05-24

Action due: 2022-06-14

Required action: Apply updates per vendor instructions.

Exploit prediction scoring system (EPSS) score for CVE-2018-19943

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 7.03% 17.71% +10.67%
2 2026-03-21 5.50% 7.03% +1.53%
3 2025-11-21 — 5.50% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-19943

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.0 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.3 6.0 [email protected]
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.3 2.7 [email protected]
3.5 2.0 LOW
AV:N/AC:M/Au:S/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 6.8 2.9 [email protected]

Weakness enumeration for CVE-2018-19943

Affected software / configurations for CVE-2018-19943

Vendor Product Version Raw CPE
qnap qts < 4.2.6 cpe:2.3:o:qnap:qts:*:*:*:*:*:*:*:*
qnap qts >= 4.3.1.0013, < 4.3.3.1252 cpe:2.3:o:qnap:qts:*:*:*:*:*:*:*:*
qnap qts >= 4.3.4, < 4.3.4.1282 cpe:2.3:o:qnap:qts:*:*:*:*:*:*:*:*
qnap qts >= 4.3.6, < 4.3.6.1263 cpe:2.3:o:qnap:qts:*:*:*:*:*:*:*:*
qnap qts >= 4.4.0, < 4.4.1.1261 cpe:2.3:o:qnap:qts:*:*:*:*:*:*:*:*
qnap qts >= 4.4.2, < 4.4.2.1270 cpe:2.3:o:qnap:qts:*:*:*:*:*:*:*:*
qnap qts 4.2.6 cpe:2.3:o:qnap:qts:4.2.6:-:*:*:*:*:*:*
qnap qts 4.2.6 cpe:2.3:o:qnap:qts:4.2.6:build_20170517:*:*:*:*:*:*
qnap qts 4.2.6 cpe:2.3:o:qnap:qts:4.2.6:build_20190322:*:*:*:*:*:*
qnap qts 4.2.6 cpe:2.3:o:qnap:qts:4.2.6:build_20190730:*:*:*:*:*:*
qnap qts 4.2.6 cpe:2.3:o:qnap:qts:4.2.6:build_20190921:*:*:*:*:*:*
qnap qts 4.2.6 cpe:2.3:o:qnap:qts:4.2.6:build_20191107:*:*:*:*:*:*
qnap qts 4.2.6 cpe:2.3:o:qnap:qts:4.2.6:build_20200109:*:*:*:*:*:*
qnap qts 4.2.6 cpe:2.3:o:qnap:qts:4.2.6:build_20200421:*:*:*:*:*:*
qnap qts 4.2.6 cpe:2.3:o:qnap:qts:4.2.6:build_20200611:*:*:*:*:*:*
qnap qts 4.2.6 cpe:2.3:o:qnap:qts:4.2.6:build_20200821:*:*:*:*:*:*

References for CVE-2018-19943

cvelogic Threat Intelligence