Stored cross-site scripting vulnerability in QES

published 2020-12-24 5y ago modified 2026-06-17 4mo ago also EUVD-2020-22296

cvss: 9.0; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.8%; EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits: 0; none known

If exploited, this stored cross-site scripting vulnerability could allow remote attackers to inject malicious code in File Station. QNAP has already fixed these issues in QES 2.1.1 Build 20201006 and later.

Patch / fix

fixed in 1

QNAP Systems Inc. QES 2.1.1

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Exploit prediction

0.79% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.0	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
NVD	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD	2.0	3.5	AV:N/AC:M/Au:S/C:N/I:P/A:N

Affected products

QNAP Systems Inc. QES

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation
CWE-80 Improper Neutralization of Script-Related HTML Tags in a Web Page
CWE-749 Exposed Dangerous Method or Function

References

qnap.com /zh-tw/security-advisory/qsa-20-17
vendor-advisory

Sources

CVE List CVE-2020-2503
NVD CVE-2020-2503

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