What is CVE-2019-18858?

CVE-2019-18858 is a critical-severity vulnerability in Codesys Control For Beaglebone, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2019-11-20.

How severe is CVE-2019-18858?

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

Buffer overflow in Codesys Control For Beaglebone

CVE-2019-18858

CODESYS 3 web server before 3.5.15.20, as distributed with CODESYS Control runtime systems, has a Buffer Overflow.

Vulnerability class: Buffer Overflow

Published 2019-11-20 · 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: 0.019 (79.4th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 79th percentile — 79.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.019 · newest: 0.019 · change: 0.000

Affected products

Weakness classification (CWE)

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

References

customers.codesys.com/fileadmin/data/customers/security/2019/Advisory2019-10_CD… (Vendor Advisory)
www.tenable.com/security/research/tra-2019-48 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2019-18858?: CVE-2019-18858 is a critical-severity vulnerability in Codesys Control For Beaglebone, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2019-11-20.
How severe is CVE-2019-18858?: Critical severity. CVSS v3 base score is 9.8 out of 10.