What is CVE-2023-40216?

CVE-2023-40216 is a medium-severity vulnerability in OpenBSD, classified under Missing Authorization. CVSS score: 5.5/10. Published 2023-08-10.

How severe is CVE-2023-40216?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Auth bypass in OpenBSD

CVE-2023-40216

OpenBSD 7.3 before errata 014 is missing an argument-count bounds check in console terminal emulation. This could cause incorrect memory access and a kernel crash after receiving crafted DCS or CSI terminal escape sequences.

Vulnerability class: Broken Access Control

Published 2023-08-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.001 (3.2th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 3.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000

Affected products

OpenBSD — versions 7.3

Weakness classification (CWE)

CWE-862 — Missing Authorization

References

ftp.openbsd.org/pub/OpenBSD/patches/7.3/common/014_wscons.patch.sig (Patch, Vendor Advisory)
github.com/openbsd/src/commit/9d3f688f46eba347e96ff0ae9506ef2061622e0c (Patch)

Frequently asked questions

What is CVE-2023-40216?: CVE-2023-40216 is a medium-severity vulnerability in OpenBSD, classified under Missing Authorization. CVSS score: 5.5/10. Published 2023-08-10.
How severe is CVE-2023-40216?: Medium severity. CVSS v3 base score is 5.5 out of 10.