How severe is CVE-2026-26239?

CVE-2026-26239 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2026-26239 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-26239?

CVE-2026-26239 affects Qnap File Station. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-26239?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-26239 have an EU (EUVD) identifier?

Yes. CVE-2026-26239 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35979.

When was CVE-2026-26239 published?

CVE-2026-26239 was published on 2026-06-10 and last updated on 2026-06-17.

CVE-2026-26239

CVE-2026-26239 is a high-severity vulnerability in Qnap File Station with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-121.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v4: 6.3
EPSS exploit prediction: 0% (21st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-35979
Weakness: CWE-121
Affected product: Qnap File Station
Published: 2026-06-10
Last modified: 2026-06-17

Description

A buffer overflow vulnerability has been reported to affect File Station 5. If a remote attacker gains a user account, they can then exploit the vulnerability to modify memory or crash processes. We have already fixed the vulnerability in the following version: File Station 5 5.5.6.5208 and later

Frequently asked questions

What is CVE-2026-26239?: A buffer overflow vulnerability has been reported to affect File Station 5. If a remote attacker gains a user account, they can then exploit the vulnerability to modify memory or crash processes. We have already fixed the vulnerability in the following version: File Station 5 5.5.6.5208 and later
How severe is CVE-2026-26239?: CVE-2026-26239 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2026-26239 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-26239?: CVE-2026-26239 affects Qnap File Station. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-26239?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-26239 have an EU (EUVD) identifier?: Yes. CVE-2026-26239 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35979.
When was CVE-2026-26239 published?: CVE-2026-26239 was published on 2026-06-10 and last updated on 2026-06-17.

References

https://www.qnap.com/en/security-advisory/qsa-26-10

Affected products (1)

cpe:2.3:a:qnap:file_station:*:*:*:*:*:*:*:*

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