DiskStation Manager (DSM): Improper Limitation of a Pathname to a Restricted Directory
CVE-2026-18792 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in DiskStation Manager (DSM) from Synology, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 7.4.1-90080-1, 7.3.2-86009-5 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 0.92% chance of exploitation within 30 days, higher than 61% of scored 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, whichever matches your release line, or a later version.
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 | 7.4.1-90080-1, 7.3.2-86009-5 |
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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (synology.com).
Official description
An improper limitation of a pathname to a restricted directory vulnerability in the Sharing API in Synology DiskStation Manager (DSM) before 7.3.2-86009-5 and 7.4.1-90080-1 allows remote authenticated users to read or write arbitrary files and conduct denial-of-service attacks.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
References
Other references
Other vulnerabilities in DiskStation Manager (DSM)
- 8.6 High severity
- 8.1 High severity
- 9.8 Critical severity
- 7.2 High severity
- 8.8 High severity
- 8.1 High severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 8.8 High severity
- 7.1 High severity
- 7.4 High severity
- 9.8 Critical severity
- 7.2 High severity
- 7.2 High severity
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