Is CVE-2026-26240 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-26240 being exploited in the wild.

How severe is CVE-2026-26240?

Informational severity, with a CVSS score of 5.3, published 10 June 2026.

Which products and versions are affected?

QNAP Systems, Inc. File Station 5 versions prior to 5.5.6.5243.

Is there a fix for CVE-2026-26240?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-26240 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-26240?

Check whether you run QNAP Systems or Inc. File Station 5 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.

CVE-2026-26240: QNAP File Station 5 stack-based buffer overflow

CVE-2026-26240 · Severity: info · CVSS 5.3 · Published 2026-06-10

QNAP File Station 5, a web-based tool for managing files on QNAP NAS devices, is affected by a security vulnerability. Remote attackers can exploit this flaw to crash the application or modify its memory, potentially disrupting file management operations. Users should update to the latest version to ensure the stability and security of their storage systems.

Technologies: QNAP Systems, Inc. File Station 5. Vendors: QNAP Systems, Inc..

Quick answers

Is CVE-2026-26240 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-26240 being exploited in the wild.
How severe is CVE-2026-26240?: Informational severity, with a CVSS score of 5.3, published 10 June 2026.
Which products and versions are affected?: QNAP Systems, Inc. File Station 5 versions prior to 5.5.6.5243.
Is there a fix for CVE-2026-26240?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-26240 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-26240?: Check whether you run QNAP Systems or Inc. File Station 5 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

A stack-based buffer overflow (CWE-121) exists in QNAP File Station 5. The vulnerability can be triggered by a remote attacker, though the CVSS vector indicates that some level of user interaction (UI:P) is required. Successful exploitation allows the attacker to modify memory or crash processes, leading to a denial-of-service condition. The issue is resolved in File Station 5 version 5.5.6.5243 and later.

Affected products

QNAP Systems, Inc. File Station 5 versions prior to 5.5.6.5243

Timeline

2026-06-10: advisory: QNAP published security advisory QSA-26-32
2026-06-10: disclosed: CVE-2026-26240 published to NVD

References

https://www.qnap.com/en/security-advisory/qsa-26-32

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