Quick answers
- Is CVE-2026-81558 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-81558 being exploited in the wild.
- How severe is CVE-2026-81558?
- Medium severity, with a CVSS score of 4.3, published 12 November 2026.
- Which products and versions are affected?
- Synology DiskStation Manager (DSM) 7.3.0 to 7.3.2-86009-4; 7.4.0 to 7.4.1-90080-0.
- Is there a fix for CVE-2026-81558?
- Yes: fixed in DSM 7.3.2-86009-5, 7.4.1-90080-1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-81558 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-81558?
- Check whether you run Synology DiskStation Manager (DSM) 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
Technical details
A missing authorization check in the SocketIo API in DSM allows remote authenticated users to write specific files without proper privilege validation (CWE-639/authorization bypass). The vulnerability requires authentication but no elevated privileges, and is exploitable over the network. An attacker with valid credentials can bypass authorization checks to modify files on the NAS device.
Affected products
- Synology DiskStation Manager (DSM) 7.3.0 to 7.3.2-86009-4; 7.4.0 to 7.4.1-90080-0
Timeline
- 2026-11-10: disclosed
- 2026-11-12: advisory