Cyber Resilience

CVE-2021-26565

HighPublic PoC

Published: 26 February 2021

Published
26 February 2021
Modified
14 January 2025
KEV Added
Patch
CVSS Score v3.1 8.3 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
EPSS Score 0.0032 55.0th percentile
Risk Priority 17 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-26565 is a high-severity Cleartext Transmission of Sensitive Information (CWE-319) vulnerability in Synology Diskstation Manager. Its CVSS base score is 8.3 (High).

Operationally, ranked in the top 45.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

Cleartext transmission of sensitive information vulnerability in synorelayd in Synology DiskStation Manager (DSM) before 6.2.3-25426-3 allows man-in-the-middle attackers to obtain sensitive information via an HTTP session.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

synology
diskstation manager
≤ 6.2.3-25426-3
synology
vs960hd firmware
all versions
synology
skynas firmware
all versions
synology
diskstation manager unified controller
3.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-319

Role-based training covers secure transmission methods, mitigating cleartext transmission of sensitive data.

addresses: CWE-319

By requiring documented security controls for information exchanges, the control reduces the risk of cleartext transmission of sensitive data.

addresses: CWE-319

Mapping transmission actions in data flows helps prevent cleartext transmission of sensitive information.

addresses: CWE-319

Settings can enforce secure transmission protocols to prevent cleartext transmission of sensitive data.

addresses: CWE-319

Policy addresses secure transport and handling of media to avoid cleartext transmission of sensitive information.

addresses: CWE-319

Enforces safeguards against cleartext transmission of CUI when data leaves organizational boundaries to external systems.

addresses: CWE-319

Explicit controls and continuous oversight on external system services prevent cleartext transmission of sensitive information over provider-managed channels.

addresses: CWE-319

Key-establishment procedures specify secure distribution channels that preclude cleartext transmission of key material.

References