# CVE-2026-74857: Synology DiskStation Manager missing critical authentication step in Auth API

Source: https://junglewise.ai/threats/cve-2026-74857-a-missing-critical-step-in-authentication-vulnerability-in-the  
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-2026-74857 · Severity: high · CVSS 8.8 · Published 2026-11-12

Synology DiskStation Manager is a management system for network-attached storage devices that organisations use to centralise file storage and backup. A flaw in its authentication process allows authenticated users to bypass security checks and read, write, or delete arbitrary files, or trigger system outages. This gives attackers who have compromised a legitimate user account the ability to escalate their access significantly.

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

## Quick answers

**Is CVE-2026-74857 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-74857 being exploited in the wild.

**How severe is CVE-2026-74857?** High severity, with a CVSS score of 8.8, published 12 November 2026.

**Which products and versions are affected?** Synology DiskStation Manager 7.3.x before 7.3.2-86009-5 and 7.4.x before 7.4.1-90080-1.

**Is there a fix for CVE-2026-74857?** Yes: fixed in 7.3.2-86009-5 (DSM 7.3), 7.4.1-90080-1 (DSM 7.4). Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-74857 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-74857?** 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 7.3.2-86009-5 (DSM 7.3), 7.4.1-90080-1 (DSM 7.4)

## Technical details

CVE-2026-74857 is a missing critical step in authentication (CWE-304) within the Auth API that allows remote authenticated users to bypass security controls and conduct arbitrary file read/write operations or denial-of-service attacks. The vulnerability affects DSM 7.3 and 7.4 before versions 7.3.2-86009-5 and 7.4.1-90080-1 respectively, and requires prior authentication to exploit (PR:L, network vector).

## Affected products

- Synology DiskStation Manager 7.3.x 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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