# CVE-2026-19048: Synology DiskStation Manager improper link resolution in thumbnail service

Source: https://junglewise.ai/threats/cve-2026-19048-an-improper-link-resolution-before-file-access-vulnerability-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-12. Updated: 2026-11-12  
License: CC BY 4.0 with a link back

CVE-2026-19048 · Severity: high · CVSS 8.1 · Published 2026-11-12

Synology DiskStation Manager is network-attached storage software that manages file access and sharing. A flaw in the thumbnail generation service allows authenticated users to write arbitrary files and cause service disruptions, potentially leading to data corruption or system compromise.

Technologies: [Synology DiskStation Manager](https://junglewise.ai/threats/technologies/diskstation-manager). Vendors: [Synology](https://junglewise.ai/threats/vendors/synology).

## Quick answers

**Is CVE-2026-19048 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-19048 being exploited in the wild.

**How severe is CVE-2026-19048?** High severity, with a CVSS score of 8.1, published 12 November 2026.

**Which products and versions are affected?** Synology DiskStation Manager before 7.3.2-86009-5 and 7.4.x before 7.4.1-90080-1.

**Is there a fix for CVE-2026-19048?** Yes: fixed in DSM 7.3.2-86009-5, 7.4.1-90080-1 or above. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-19048 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-19048?** Check whether you run Synology DiskStation Manager at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in DSM 7.3.2-86009-5, 7.4.1-90080-1 or above

## Technical details

An improper link resolution vulnerability (CWE-59) in the thumbnail service fails to properly validate symbolic links before file access, allowing authenticated attackers to write files outside intended directories. The vulnerability requires authentication and network access; no user interaction is needed. An attacker can write arbitrary files or trigger denial-of-service conditions on the NAS device.

## Affected products

- Synology DiskStation Manager before 7.3.2-86009-5 and 7.4.x before 7.4.1-90080-1

## Timeline

- 2026-11-10: disclosed
- 2026-11-12: advisory

## References

- [https://www.synology.com/en-global/security/advisory/Synology_SA_26_18](https://www.synology.com/en-global/security/advisory/Synology_SA_26_18)

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