What is CVE-2018-0721?

CVE-2018-0721 is a high-severity vulnerability in QNAP Qts, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 7.7/10. Published 2018-11-27.

How severe is CVE-2018-0721?

High severity. CVSS v3 base score is 7.7 out of 10.

Buffer overflow in QNAP Qts

CVE-2018-0721

Buffer Overflow vulnerability in NAS devices. QTS allows attackers to run arbitrary code. This issue affects: QNAP Systems Inc. QTS version 4.2.6 and prior versions on build 20180711; version 4.3.3 and prior versions on build 20180725; version 4.3.4 and prior versions on build 20180710.

Vulnerability class: Buffer Overflow

Published 2018-11-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.7 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:H/A:L.

EPSS exploit prediction

EPSS: 0.016 (74.1th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 74th percentile — 74.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: 0.000

Affected products

QNAP Qts — versions 4.2.6, 4.3.3, 4.3.4
QNAP Systems Inc. Qts — versions unspecified

Weakness classification (CWE)

References

www.qnap.com/zh-tw/security-advisory/nas-201809-20 (Vendor Advisory)

Frequently asked questions

What is CVE-2018-0721?: CVE-2018-0721 is a high-severity vulnerability in QNAP Qts, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 7.7/10. Published 2018-11-27.
How severe is CVE-2018-0721?: High severity. CVSS v3 base score is 7.7 out of 10.