Vulnerability · Published Sep 18, 2026 · Assigned by synology
CVE-2026-40539
High 7.1
In plain English
A high-severity improper certificate validation in DiskStation Manager (DSM) from Synology. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities).
Severity (CVSS 3.1)7.1High
Exploit odds (30 days)0.1%top 98.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Synology | DiskStation Manager (DSM) | 7.3 – before 7.3.2-86009-27.2.2 – before 7.2.2-72806-77.2.1 – before 7.2.1-69057-10 |
Weakness: CWE-295 · Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- Synology-SA-26:06 DSM vendor-advisory