How severe is CVE-2026-4566?

CVE-2026-4566 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-4566 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-4566?

CVE-2026-4566 affects Belkin F9k1122 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-4566?

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-2026-4566 have an EU (EUVD) identifier?

Yes. CVE-2026-4566 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14347.

When was CVE-2026-4566 published?

CVE-2026-4566 was published on 2026-03-23 and last updated on 2026-06-17.

CVE-2026-4566

CVE-2026-4566 is a high-severity vulnerability in Belkin F9k1122 Firmware with a CVSS 3.x base score of 8.8. 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-119.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 9.0
CVSS v4: 7.4
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-14347
Weakness: CWE-119
Affected product: Belkin F9k1122 Firmware
Published: 2026-03-23
Last modified: 2026-06-17

Description

A flaw has been found in Belkin F9K1122 1.00.33. The affected element is the function formWISP5G of the file /goform/formWISP5G. Executing a manipulation of the argument webpage can lead to stack-based buffer overflow. The attack can be launched remotely. The exploit has been published and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Frequently asked questions

What is CVE-2026-4566?: A flaw has been found in Belkin F9K1122 1.00.33. The affected element is the function formWISP5G of the file /goform/formWISP5G. Executing a manipulation of the argument webpage can lead to stack-based buffer overflow. The attack can be launched remotely. The exploit has been published and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
How severe is CVE-2026-4566?: CVE-2026-4566 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-4566 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-4566?: CVE-2026-4566 affects Belkin F9k1122 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-4566?: 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-2026-4566 have an EU (EUVD) identifier?: Yes. CVE-2026-4566 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14347.
When was CVE-2026-4566 published?: CVE-2026-4566 was published on 2026-03-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:belkin:f9k1122_firmware:1.00.33:*:*:*:*:*:*:*

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