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HIGH

CVE-2026-40539

CVSS v3

7.1

HIGH

EPSS Score

0.1 %

exploit probability, as of 2026-09-28

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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.

Technical details

Published
2026-09-18
Last Modified
2026-09-18

Frequently asked questions

What is CVE-2026-40539?

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.

Is CVE-2026-40539 actively exploited?

Active exploitation of CVE-2026-40539 has not been confirmed. Its EPSS score was 0.1% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-40539?

CVE-2026-40539 has a CVSS v3 base score of 7.1 (HIGH severity).

Is CVE-2026-40539 affecting your environment?

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