DiskStation Manager (DSM): Authentication Bypass Using an Alternate Path or Channel
CVE-2026-85101 is a high-severity authentication bypass using an alternate path or channel vulnerability in DiskStation Manager (DSM) from Synology, with a CVSS 3.1 base score of 8.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 7.4.1-90080-1, 7.3.2-86009-5, 7.2.2-72806-10 as the first without the flaw, so updating DiskStation Manager (DSM) to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.58% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update DiskStation Manager (DSM) to 7.4.1-90080-1 or 7.3.2-86009-5 or 7.2.2-72806-10 or 7.2.1-69057-13, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Synology | DiskStation Manager (DSM) | 7.4.1 up to, but not including, 7.4.1-90080-1; 7.3.2 up to, but not including, 7.3.2-86009-5; 7.2.2 up to, but not including, 7.2.2-72806-10; 7.2.1 up to, but not including, 7.2.1-69057-13 | 7.4.1-90080-1, 7.3.2-86009-5, 7.2.2-72806-10, 7.2.1-69057-13 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L. Scored by CNA (synology.com).
Official description
An authentication bypass using an alternate path or channel vulnerability in the rsync in Synology DiskStation Manager (DSM) before 7.2.1-69057-13, 7.2.2-72806-10, 7.3.2-86009-5, and 7.4.1-90080-1 allows remote attackers to read specific files, write arbitrary files, and conduct limited denial-of-service attacks.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authentication Bypass Using an Alternate Path or Channel
The product requires authentication, but the product has an alternate path or channel that does not require authentication.
How developers prevent this class of flaw
- Funnel all access through a single choke point to simplify how users can access a resource. For every access, perform a check to determine if the user has permissions to access the resource.
More Authentication Bypass Using an Alternate Path or Channel vulnerabilities (CWE-288)
Timeline
- CVE record published.
References
Other references
Other vulnerabilities in DiskStation Manager (DSM)
- 8.1 High severity
- 9.8 Critical severity
- 7.2 High severity
- 8.8 High severity
- 8.1 High severity
- 8.8 High severity
Recent Authentication Bypass Using an Alternate Path or Channel vulnerabilities
- 8.7 High severity
- 8.8 High severity
- 9.3 Critical severity
- 8.1 High severity
- 7.5 High severity
- 9.8 Critical severity
Spotted an error? Tell us.