CVE-2018-19953

Exp

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.

Published: 2020-10-28 Last update: 2025-11-03 Assigner: [email protected] Source: [email protected]

NVD Status：Analyzed，CVE State: published

View at NVD, CVE.org, EUVD

Threat Intelligence & Risk Assessment for CVE-2018-19953

KEV EPSS CVSS CWE Affected

Conclusion & alert: CVE-2018-19953 is rated Critical Active Threat (88.2/100): CVSS Medium severity, with high exploitation likelihood (EPSS 31.52%, 97th percentile). Core evidence: 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 +18.69% over the last day, indicating growing attacker interest. Mandatory action: 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-2018-19953

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-2018-19953

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	2025-11-21	12.83%	31.52%	+18.69%
2	2025-11-18	31.52%	12.83%	-18.69%
3	2025-11-04	—	31.52%	—

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-19953

CVSS metrics for this CVE.

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
6.1	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/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:N) No account or special rights needed—anonymous or random user is enough. 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.	2.8	2.7	[email protected]
6.1	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/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:N) No account or special rights needed—anonymous or random user is enough. 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.	2.8	2.7	134c704f-9b21-4f2e-91b3-4a467353bcc0
4.3	2.0	MEDIUM	`AV:N/AC:M/Au:N/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:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:N) No availability impact.	8.6	2.9	[email protected]

Weakness enumeration for CVE-2018-19953

CWE-79 MITRE ↗ CWE-80 MITRE ↗

Affected software / configurations for CVE-2018-19953

Vendor	Product	Version	Raw CPE
qnap	qts	< 4.2.6	cpe:2.3:o:qnap:qts::::::::
qnap	qts	>= 4.3.1.0013, < 4.3.3.1161	cpe:2.3:o:qnap:qts::::::::
qnap	qts	>= 4.3.4, < 4.3.4.1190	cpe:2.3:o:qnap:qts::::::::
qnap	qts	>= 4.3.6, < 4.3.6.1218	cpe:2.3:o:qnap:qts::::::::
qnap	qts	>= 4.4.0, < 4.4.1.1201	cpe:2.3:o:qnap:qts::::::::
qnap	qts	>= 4.4.2, < 4.4.2.1231	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::::::

References for CVE-2018-19953

URL	Tags
https://www.qnap.com/zh-tw/security-advisory/qsa-20-01	Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-19953	US Government Resource

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