CVE-2026-40539 — HIGH (7.1)

Vulnerability Description

An improper certificate validation vulnerability in Email API in Synology DiskStation Manager (DSM) before 7.2.1-69057-10, 7.2.2-72806-7 and 7.3.2-86009-2 allows man-in-the-middle attackers to read or write arbitrary files and conduct denial-of-service attacks.

CVSS Score

7.1

HIGH

CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector

ADJACENT_NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

HIGH

Related Weaknesses (CWE)

CWE-295

References

https://www.synology.com/en-global/security/advisory/Synology_SA_26_06

FAQ

What is CVE-2026-40539?

CVE-2026-40539 is a vulnerability with a CVSS score of 7.1 (HIGH). An improper certificate validation vulnerability in Email API in Synology DiskStation Manager (DSM) before 7.2.1-69057-10, 7.2.2-72806-7 and 7.3.2-86009-2 allows man-in-the-middle attackers to read or...

How severe is CVE-2026-40539?

CVE-2026-40539 has been rated HIGH with a CVSS base score of 7.1/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-40539?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.