CVE-2021-26565
Cleartext transmission of sensitive information vulnerability in synorelayd in Synology...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
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.
- Record
CVE-2021-26565- CVSS 3.1
- 8.3 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H - Weakness
- CWE-319
- Updated
- 2026-11-02
EUVDEUVD-2021-13363
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.
- Record
EUVD-2021-13363- CVSS 3.1
- 8.3 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-8rp4-gqh3-jpxm
Cleartext transmission of sensitive information vulnerability in synorelayd in Synology...
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.
- Record
GHSA-8rp4-gqh3-jpxm- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-319
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-26565- CVSS 3.1
- 8.3 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H - CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:P/I:N/A:N - Weakness
- CWE-319
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-26565 is a high vulnerability (CVSS 8.3) in Synology Diskstation Manager, published February 26, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.74%, the 54th percentile. No source names a fixed version.