How severe is CVE-2025-66635?

CVE-2025-66635 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-66635 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-66635?

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-2025-66635 have an EU (EUVD) identifier?

Yes. CVE-2025-66635 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-203525.

When was CVE-2025-66635 published?

CVE-2025-66635 was published on 2025-12-16 and last updated on 2026-06-17.

CVE-2025-66635

CVE-2025-66635 is a high-severity vulnerability with a CVSS 3.x base score of 7.2. 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 7.2)
CVSS v4: 8.6
EPSS exploit prediction: 0% (39th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-203525
Weakness: CWE-121
Published: 2025-12-16
Last modified: 2026-06-17

Description

Stack-based buffer overflow vulnerability exists in SEIKO EPSON Web Config. Specially crafted data input by a logged-in user may execute arbitrary code. As for the details of the affected products and versions, see the information provided by the vendor under [References].

Frequently asked questions

What is CVE-2025-66635?: Stack-based buffer overflow vulnerability exists in SEIKO EPSON Web Config. Specially crafted data input by a logged-in user may execute arbitrary code. As for the details of the affected products and versions, see the information provided by the vendor under [References].
How severe is CVE-2025-66635?: CVE-2025-66635 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-66635 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-66635?: 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-2025-66635 have an EU (EUVD) identifier?: Yes. CVE-2025-66635 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-203525.
When was CVE-2025-66635 published?: CVE-2025-66635 was published on 2025-12-16 and last updated on 2026-06-17.

References

Other CWE-121 (Stack-based Buffer Overflow) vulnerabilities

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