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Vulnerability record · CVE-2021-38691 · published 14 January 2022

CVE-2021-38691: Qnap qvr elite classic buffer overflow vulnerability

Qnap · Qvr Elite

A stack buffer overflow vulnerability has been reported to affect QNAP device running QVR Elite, QVR Pro, QVR Guard. If exploited, this vulnerability allows attackers to execute arbitrary code. We have already fixed this vulnerability in the following versions of QVR Elite, QVR Pro, QVR Guard: QuTS hero h5.0.0: QVR Elite 2.1.4.0 (2021/12/06) and later QuTS hero h4.5.4: QVR Elite 2.1.4.0 (2021/12/06) and later QTS 5.0.0: QVR Elite 2.1.4.0 (2021/12/06) and later QTS 4.5.4: QVR Elite 2.1.4.0 (2021/12/06) and later QTS 4.5.4: QVR Pro 2.1.3.0 (2021/12/06) and later QTS 5.0.0: QVR Pro 2.1.3.0 (2021/12/06) and later QTS 4.5.4: QVR Guard 2.1.3.0 (2021/12/06) and later QTS 5.0.0: QVR Guard 2.1.3.0 (2021/12/06) and later

9.8 CVSS 3.1 Critical EPSS 1.3% · top 30.8% CWE-120 · Classic buffer overflowCWE-787 · Out-of-bounds write
9.8CVSS 3.1 base score, v2 7.5
1.3%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

A stack buffer overflow vulnerability has been reported to affect QNAP device running QVR Elite, QVR Pro, QVR Guard. If exploited, this vulnerability allows attackers to execute arbitrary code. We have already fixed this vulnerability in the following versions of QVR Elite, QVR Pro, QVR Guard: QuTS hero h5.0.0: QVR Elite 2.1.4.0 (2021/12/06) and later QuTS hero h4.5.4: QVR Elite 2.1.4.0 (2021/12/06) and later QTS 5.0.0: QVR Elite 2.1.4.0 (2021/12/06) and later QTS 4.5.4: QVR Elite 2.1.4.0 (2021/12/06) and later QTS 4.5.4: QVR Pro 2.1.3.0 (2021/12/06) and later QTS 5.0.0: QVR Pro 2.1.3.0 (2021/12/06) and later QTS 4.5.4: QVR Guard 2.1.3.0 (2021/12/06) and later QTS 5.0.0: QVR Guard 2.1.3.0 (2021/12/06) and later

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

3 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://www.qnap.com/en/security-advisory/qsa-21-59 Vendor Advisory
https://www.qnap.com/en/security-advisory/qsa-21-59 Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-38691), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.