Codesys vulnerabilities

13 CVEs affecting Codesys, 0 known to be exploited (CISA KEV), with EPSS scores. Latest: CVE-2025-41700, published 2025-12-01.

Highest priority

Known exploited (CISA KEV) first, then by EPSS exploit probability.

CVE-2021-34586, published 2021-10-26. High severity, CVSS 7.5. EPSS: 14.1% chance of exploitation in the next 30 days. In the CODESYS V2 web server prior to V1.1.9.22 crafted web server requests may cause a Null pointer dereference in the CODESYS web server and may result in a denial-of-service condition.
CVE-2021-34583, published 2021-10-26. High severity, CVSS 7.5. EPSS: 8.4% chance of exploitation in the next 30 days. Crafted web server requests may cause a heap-based buffer overflow and could therefore trigger a denial-of- service condition due to a crash in the CODESYS V2 web server prior to V1.1.9.22.
CVE-2019-5105, published 2020-03-26. High severity, CVSS 7.5. EPSS: 2.2% chance of exploitation in the next 30 days. An exploitable memory corruption vulnerability exists in the Name Service Client functionality of 3S-Smart Software Solutions CODESYS GatewayService. A specially crafted packet can cause a large…
CVE-2021-21869, published 2021-08-25. High severity, CVSS 7.8. EPSS: 1.8% chance of exploitation in the next 30 days. An unsafe deserialization vulnerability exists in the Engine.plugin ProfileInformation ProfileData functionality of CODESYS GmbH CODESYS Development System 3.5.16 and 3.5.17. A specially crafted file…
CVE-2021-21867, published 2021-08-18. High severity, CVSS 7.8. EPSS: 1.6% chance of exploitation in the next 30 days. An unsafe deserialization vulnerability exists in the ObjectManager.plugin ObjectStream.ProfileByteArray functionality of CODESYS GmbH CODESYS Development System 3.5.16 and 3.5.17. A specially…
CVE-2019-16265, published 2019-10-25. Critical severity, CVSS 9.8. EPSS: 1.6% chance of exploitation in the next 30 days. CODESYS V2.3 ENI server up to V3.2.2.24 has a Buffer Overflow.
CVE-2021-21868, published 2021-08-18. High severity, CVSS 7.8. EPSS: 1.6% chance of exploitation in the next 30 days. An unsafe deserialization vulnerability exists in the ObjectManager.plugin Project.get_MissingTypes() functionality of CODESYS GmbH CODESYS Development System 3.5.16 and 3.5.17. A specially crafted…
CVE-2021-34584, published 2021-10-26. Critical severity, CVSS 9.1. EPSS: 1.1% chance of exploitation in the next 30 days. Crafted web server requests can be utilised to read partial stack or heap memory or may trigger a denial-of- service condition due to a crash in the CODESYS V2 web server prior to V1.1.9.22.
CVE-2021-34585, published 2021-10-26. High severity, CVSS 7.5. EPSS: 0.9% chance of exploitation in the next 30 days. In the CODESYS V2 web server prior to V1.1.9.22 crafted web server requests can trigger a parser error. Since the parser result is not checked under all conditions, a pointer dereference with an…
CVE-2021-34595, published 2021-10-26. High severity, CVSS 8.1. EPSS: 0.9% chance of exploitation in the next 30 days. A crafted request with invalid offsets may cause an out-of-bounds read or write access in CODESYS V2 Runtime Toolkit 32 Bit full and PLCWinNT prior to versions V2.4.7.56, resulting in a…

Latest

CVE-2025-41700, published 2025-12-01. High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days. An unauthenticated attacker can trick a local user into executing arbitrary code by opening a deliberately manipulated CODESYS project file with a CODESYS development system. This arbitrary code is…
CVE-2021-34596, published 2021-10-26. Medium severity, CVSS 6.5. EPSS: 0.9% chance of exploitation in the next 30 days. A crafted request may cause a read access to an uninitialized pointer in CODESYS V2 Runtime Toolkit 32 Bit full and PLCWinNT prior to versions V2.4.7.56, resulting in a denial-of-service condition.