Cyber Posture

CVE-2021-47807

HighPublic PoC

Published: 16 January 2026

Published
16 January 2026
Modified
30 January 2026
KEV Added
Patch
CVSS Score 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0001 0.4th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-47807 is a high-severity Unquoted Search Path or Element (CWE-428) vulnerability in Flexense Sync Breeze. Its CVSS base score is 7.8 (High).

Operationally, ranked at the 0.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 CM-6 (Configuration Settings) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

Requires establishment and implementation of secure configuration settings for services, directly preventing exploitation of unquoted service paths like in CVE-2021-47807.

prevent

Mandates identification, reporting, and timely correction of flaws such as the unquoted service path vulnerability in Sync Breeze.

detect

Vulnerability scanning identifies configuration issues like unquoted service paths, enabling remediation before exploitation.

NVD Description

Sync Breeze 13.6.18 contains an unquoted service path vulnerability in its Windows service configuration that allows local attackers to potentially execute arbitrary code. Attackers can exploit the unquoted path in service binaries located in 'Program Files' directories to inject malicious…

more

executables and escalate privileges.

Deeper analysisAI

CVE-2021-47807 is an unquoted service path vulnerability in Sync Breeze version 13.6.18. The issue resides in the Windows service configuration, where service binaries located in 'Program Files' directories use unquoted paths, allowing potential arbitrary code execution. It is classified under CWE-428 and carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Local attackers can exploit this vulnerability by injecting malicious executables into paths that the service resolves due to the unquoted service path. With low-privilege access on the system, attackers can achieve privilege escalation upon service restart or execution.

Advisories, including VulnCheck's note on multiple unquoted service paths in Sync Breeze and the vendor site at https://www.syncbreeze.com/, provide further details on the issue. A proof-of-concept exploit is available at https://www.exploit-db.com/exploits/50023.

Details

CWE(s)

Affected Products

flexense
sync breeze
13.6.18

CVEs Like This One

CVE-2021-47809Same vendor: Flexense
CVE-2020-37100Same vendor: Flexense
CVE-2020-36930Same vendor: Flexense
CVE-2021-47806Same vendor: Flexense
CVE-2021-47805Same vendor: Flexense
CVE-2020-36927Same vendor: Flexense
CVE-2025-59893Same vendor: Flexense
CVE-2025-59891Same vendor: Flexense
CVE-2020-36946Same vendor: Flexense
CVE-2025-59894Same vendor: Flexense

References