What is CVE-2023-36659?

CVE-2023-36659 is a critical-severity vulnerability in Opswat Metadefender Kiosk, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2023-09-15.

How severe is CVE-2023-36659?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Opswat Metadefender Kiosk

CVE-2023-36659

An issue was discovered in OPSWAT MetaDefender KIOSK 4.6.1.9996. Long inputs were not properly processed, which allows remote attackers to cause a denial of service (loss of communication).

Vulnerability class: Buffer Overflow

Published 2023-09-15 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.010 (60.9th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 60.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.010 · change: +0.003

Affected products

Opswat Metadefender Kiosk

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

docs.opswat.com/mdkiosk (Product, Release Notes)
docs.opswat.com/mdkiosk/release-notes/cve-2023-36659 (Release Notes, Vendor Advisory)

Frequently asked questions

What is CVE-2023-36659?: CVE-2023-36659 is a critical-severity vulnerability in Opswat Metadefender Kiosk, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2023-09-15.
How severe is CVE-2023-36659?: Critical severity. CVSS v3 base score is 9.8 out of 10.