Is CVE-2026-26240 in the CISA KEV catalog?

No. CVE-2026-26240 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-26240?

CVE-2026-26240 has a CVSS v3 base score of 9.1 (CRITICAL).

What is the EPSS score for CVE-2026-26240?

CVE-2026-26240 has an EPSS score of 0.32% (23th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-26240

CRITICAL

9.1

CVSS v3

NVD

Description

A buffer overflow vulnerability has been reported to affect File Station 5. The remote attackers can then exploit the vulnerability to modify memory or crash processes. We have already fixed the vulnerability in the following version: File Station 5 5.5.6.5243 and later

CWE-121

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Exploit Intelligence

0.32%probability of exploitation in 30 days

23rdpercentile

Low risk: more likely to be exploited than 23% of all known CVEs.

References

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

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-12.