# CVE-2026-40531: Synology DiskStation Manager integer overflow in File Operation

Source: https://junglewise.ai/threats/cve-2026-40531-synology-diskstation-manager-integer-overflow-in-file-operation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-18. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-40531 · Severity: medium · CVSS 4.3 · Published 2026-09-18

Synology DiskStation Manager (DSM) is a central operating system for Synology NAS devices that manages storage, files, and user access. A flaw in the File Operation component allows authenticated users to trigger a denial-of-service condition, potentially causing service interruptions for all users accessing the NAS.

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

## Quick answers

**Is CVE-2026-40531 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-40531 being exploited in the wild.

**How severe is CVE-2026-40531?** Medium severity, with a CVSS score of 4.3, published 18 September 2026.

**Which products and versions are affected?** Synology DiskStation Manager (DSM) before 7.2.1-69057-10, before 7.2.2-72806-7, before 7.3.2-86009-2.

**Is there a fix for CVE-2026-40531?** A patch was published on 2026-04-15: Patches released for DSM 7.2.1, 7.2.2, and 7.3 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-40531 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-40531?** 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.

## Technical details

An integer overflow or wraparound vulnerability (CWE-190) exists in the File Operation component of Synology DSM. The vulnerability requires remote network access and valid user authentication credentials; no special privileges or user interaction is needed. An authenticated attacker can trigger limited denial-of-service attacks by exploiting the integer overflow. Patches are available: DSM 7.2.1-69057-10, DSM 7.2.2-72806-7, and DSM 7.3.2-86009-2 or later.

## Affected products

- Synology DiskStation Manager (DSM) before 7.2.1-69057-10, before 7.2.2-72806-7, before 7.3.2-86009-2

## Timeline

- 2026-04-15: disclosed
- 2026-04-15: patched: Patches released for DSM 7.2.1, 7.2.2, and 7.3
- 2026-09-18: advisory

## References

- [https://www.synology.com/en-global/security/advisory/Synology_SA_26_06](https://www.synology.com/en-global/security/advisory/Synology_SA_26_06)

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