CVE-2021-38687: QNAP Surveillance Station

Critical severity, CVSS 9.8. EPSS: 1.3% chance of exploitation in the next 30 days.

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

Affected products

• QNAP Surveillance Station: before 5.2.0.4.2 (fixed in 5.2.0.4.2); before 5.2.0.3.2 (fixed in 5.2.0.3.2); before 5.1.5.4.6 (fixed in 5.1.5.4.6); before 5.1.5.3.6 (fixed in 5.1.5.3.6)

Published 2021-12-29. Last modified 2026-06-17.