Improper Limitation of a Pathname to a Restricted Directory in QTS

published 2020-12-31 5 y ago modified 2026-06-17 4 mo ago also EUVD-2018-11616

cvss: 9.1; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.1%; EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits: 0; none known

A vulnerability has been reported to affect earlier QNAP devices running QTS 4.3.4 to 4.3.6. Caused by improper limitations of a pathname to a restricted directory, this vulnerability allows for renaming arbitrary files on the target system, if exploited. QNAP have already fixed this vulnerability in the following versions: QTS 4.3.6.0895 build 20190328 (and later) QTS 4.3.4.0899 build 20190322 (and later) This issue does not affect QTS 4.4.x or QTS 4.5.x.

Patch / fix

fixed in 1

QNAP Systems Inc. QTS 4.3.4.0899, 4.3.6.0895

Exploit prediction

1.12% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
NVD	2.0	8.5	AV:N/AC:L/Au:N/C:N/I:P/A:C

Affected products

QNAP Systems Inc. QTS

Classification

Weakness

CWE-20 Improper Input Validation
CWE-22 Improper Limitation of a Pathname to a Restricted Directory
CWE-73 External Control of File Name or Path
CWE-284 Improper Access Control

References

qnap.com /zh-tw/security-advisory/qsa-20-21
vendor-advisory

Sources

CVE List CVE-2018-19945
NVD CVE-2018-19945

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Summary