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

CVSS: 8.0v3.1HighKEVRansomwareAnalyzed
Published 28-10-2020Last modified 13-08-2026
Open JSON

Vulnerability summary

CVE-2018-19943 is a high (CVSS 8.0) Cross-site Scripting vulnerability in QNAP Network Attached Storage (NAS). It is known to be exploited: CISA lists it, first on 24-05-2022. It has been used in ransomware campaigns. EPSS estimates a 21.48% chance of exploitation in the next 30 days, higher than 97.5% of scored vulnerabilities.

Overall risk
90/100
0100
Critical · default modelHow is this calculated?
CVSS score
8.0/10
010
High · v3.1 (CVE.org)
EPSS score
21.48%
0%100%
High · +3.77 pp in 30 days
KEVListedCISA
RansomwareKnown useFlagged by CISA
Public exploits0No public exploits recorded

Timeline

  1. 28-10-2020
    PublishedVulnerability first disclosed.
  2. 24-05-2022
    Added to CISA KEVQNAP NAS File Station Cross-Site Scripting Vulnerability
  3. 14-06-2022
    CISA remediation dueApply updates per vendor instructions.
  4. 13-08-2026
    Last modifiedVulnerability information updated.

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

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

21.48%

Chance of exploitation in the next 30 days

Percentile

98%

Versus all other CVEs

30-day change

+3.77 pp

From 17.71% on 19-09-2026

19-09-202619-10-2026
EPSS score
21.48%

Known exploited

Compare KEV catalogs
CISA KEVListed
Added
24-05-2022
Federal due date
14-06-2022
Ransomware

CISA required action

Apply updates per vendor instructions. nvd.nist.gov/vuln/detail/CVE-2018-19943

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Qnap1 product
  • qts< 4.2.6 | ≥ 4.3.1.0013, < 4.3.3.1252 | ≥ 4.3.4, < 4.3.4.1282 | ≥ 4.3.6, < 4.3.6.1263 | ≥ 4.4.0, < 4.4.1.1261 | ≥ 4.4.2, < 4.4.2.1270 | 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:build_20200611 | 4.2.6:build_20200821
Qnap systems inc.1 product
  • qts≥ unspecified, < 4.4.2.1270 | ≥ unspecified, < 4.4.1.1261 | ≥ unspecified, < 4.3.6.1263 | ≥ unspecified, < 4.3.4.1282 | ≥ unspecified, < 4.3.3.1252 | ≥ unspecified, < 4.2.6

2 vendors · 2 products

References

2 links