CVE-2018-5440: 3s-Software Codesys Runtime System

Critical severity, CVSS 9.8. EPSS: 3.1% chance of exploitation in the next 30 days.

A Stack-based Buffer Overflow issue was discovered in 3S-Smart CODESYS Web Server. Specifically: all Microsoft Windows (also WinCE) based CODESYS web servers running stand-alone Version 2.3, or as part of the CODESYS runtime system running prior to Version V1.1.9.19. A crafted request may cause a buffer overflow and could therefore execute arbitrary code on the web server or lead to a denial-of-service condition due to a crash in the web server.

Affected products

• 3s-Software Codesys Runtime System: before 1.1.9.19 (fixed in 1.1.9.19)
• 3s-Software Codesys Web Server: version 2.3 only

Published 2018-02-15. Last modified 2026-06-17.