EUVD-2026-82797
GHSA-mqfj-89cq-4gj9
Severity by source
AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
MITM positioning gives AV:A/AC:H and no DSM auth (PR:N); an email action must be triggered (UI:R); the advisory's arbitrary file read/write plus DoS justify C:H/I:H/A:H, S:U.
Primary rating from Vendor (synology).
CVSS VectorVendor: synology
Lifecycle Timeline
3DescriptionCVE.org
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.
Articles & Coverage 1
AnalysisAI
Man-in-the-middle attackers positioned on the network path between a Synology DiskStation and its configured mail server can exploit improper TLS certificate validation in the DSM Email API to read or write arbitrary files and trigger denial-of-service conditions. The flaw affects DSM builds before 7.2.1-69057-10, 7.2.2-72806-7 and 7.3.2-86009-2, and is rated CVSS 7.1 with an adjacent-network, high-complexity, unauthenticated vector requiring some user interaction. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Requires the attacker to hold a man-in-the-middle position on the network path between the DiskStation and its configured mail server, exploiting DSM's Email API failure to validate the mail server's TLS certificate. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | This is a genuine but hard-to-exploit man-in-the-middle vulnerability, not a slam-dunk critical. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Vendor-released patch: administrators should upgrade DSM to 7.2.1-69057-10, 7.2.2-72806-7 or 7.3.2-86009-2 (whichever matches their update track) as documented in Synology security advisory SA_26_06 (https://www.synology.com/en-global/security/advisory/Synology_SA_26_06), applied via DSM Control Panel > Update & Restore. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory every Synology DiskStation running a DSM build prior to 7.2.1-69057-10, 7.2.2-72806-7 or 7.3.2-86009-2 and determine which of them have the Email API or mail notifications actively configured against an SMTP relay; on those systems, disable email notifications and the Email API until a fix ships, and open a Synology support case citing CVE-2026-40539 to secure a committed release date for the patched builds. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
More in Diskstation Manager Dsm
View allSynology DiskStation Manager (DSM) login logic uses insufficiently random values, letting remote unauthenticated attacke
Improper output encoding in the SCGI service of Synology DiskStation Manager (DSM) lets unauthenticated remote attackers
Authenticated remote attackers holding low-privileged credentials can exploit an incorrect permission assignment in the
An external control of file name or path flaw in the Synology DiskStation Manager (DSM) Upload API allows remote authent
CRLF injection in the Synology DiskStation Manager (DSM) User API lets a remote, low-privileged authenticated user (PR:L
Unauthenticated path traversal in the Synology DiskStation Manager (DSM) Desktop API allows remote attackers to write a
Information disclosure in Synology DiskStation Manager (DSM) allows remote authenticated users to obtain sensitive infor
An authenticated SQL injection in the Sharing API of Synology DiskStation Manager (DSM) allows remote users with valid -
Cross-site scripting in the Video API of Synology DiskStation Manager (DSM) allows a remote authenticated user to read o
Unauthenticated remote attackers can query the Desktop API in Synology DiskStation Manager (DSM) to retrieve non-sensiti
Improper encoding and escaping of output in the Auth API of Synology DiskStation Manager (DSM) lets remote, unauthentica
Cross-site scripting in the Synology DiskStation Manager (DSM) Theme API lets a remote attacker who already holds DSM ad
Same weakness CWE-295 – Improper Certificate Validation
View allSame technique Information Disclosure
View allShare
External POC / Exploit Code
Leaving vuln.today