CVE-2021-38687
QNAP
- Published
- 29 December 2021
- Last modified
- 17 June 2026
- CVSS
- 9.8 v3.1
- Severity
- critical
- EPSS
- 1.3% (68th pct)
- CISA KEV
- Not listed
- NVD status
- Modified
- Weaknesses
- CWE-120
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Description
A stack buffer overflow vulnerability has been reported to affect QNAP NAS running Surveillance Station. If exploited, this vulnerability allows attackers to execute arbitrary code. We have already fixed this vulnerability in the following versions of Surveillance Station: QTS 5.0.0 (64 bit): Surveillance Station 5.2.0.4.2 ( 2021/10/26 ) and later QTS 5.0.0 (32 bit): Surveillance Station 5.2.0.3.2 ( 2021/10/26 ) and later QTS 4.3.6 (64 bit): Surveillance Station 5.1.5.4.6 ( 2021/10/26 ) and later QTS 4.3.6 (32 bit): Surveillance Station 5.1.5.3.6 ( 2021/10/26 ) and later QTS 4.3.3: Surveillance Station 5.1.5.3.6 ( 2021/10/26 ) and later
Exploitation
Not listed in the CISA Known Exploited Vulnerabilities catalogue as of 2026.09.04. That is an absence of confirmed public exploitation, not evidence that exploitation has not occurred. EPSS models a 1.3% probability of exploitation activity in the next 30 days.
Affected products
| Product | Vendor | Type | Versions named |
|---|---|---|---|
| Surveillance Station | QNAP | Video management software | < 5.1.5.3.3, < 5.1.5.3.6, < 5.1.5.4.3, < 5.1.5.4.6 +3 |
References
Vendor advisory and patch
- https://www.qnap.com/en/security-advisory/qsa-21-46
- https://www.qnap.com/en/security-advisory/qsa-21-46
Record assembled from NVD, CISA KEV 2026.09.04 and FIRST EPSS 2026-09-04. Affected products are those NVD's CPE configuration names that fall inside this site's scope; a CVE may affect products outside it.