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TI-2026-27379 Aliases CVE-2026-35227GHSA-qc33-pwh4-j9rq

Improper resource management in CODESYS Modbus TCP Server

Priority LOW 36CWE-772Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-772.

Summary

An unauthenticated remote attacker may exhaust all available TCP connections in the CODESYS Modbus TCP Server stack if a race condition in connection handling is successfully exploited, preventing legitimate clients from establishing new connections.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00351 28th percentileScored 2026-11-07
Fix Fixed CODESYS Modbus (CODESYS): 4.6.0.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
CODESYSCODESYS Modbus1.0.0.0 to before 4.6.0.04.6.0.0Patch availableCNA
  • CODESYS Modbus VendorCODESYS Affected 1.0.0.0 to before 4.6.0.0 Fixed in 4.6.0.0 Patch available CNA

Remediation

  • Fix · CNA CODESYS Modbus (CODESYS) Fixed in 4.6.0.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-35227
  2. 2026-10-03 Alias added: GHSA-qc33-pwh4-j9rq

References

Other 1

  • TI-2021-12888 CODESYS Control Runtime system before 3.5.17.10 has a Heap-based Buffer Overflow. CVSS 3.1CRITICAL 9.8
  • TI-2019-10180 Stack-based buffer overflow in CODESYS V3 web server CVSS 3.1CRITICAL 9.8
  • TI-2021-13604 CODESYS V2 web server: crafted requests could trigger a null pointer dereference (DoS) CVSS 3.1HIGH 7.5
  • TI-2020-08257 CODESYS V3 web server before 3.5.15.40, as used in CODESYS Control runtime systems, has a buffer overflow. CVSS 3.1CRITICAL 9.8
  • TI-2019-13592 CODESYS 3 web server before 3.5.15.20, as distributed with CODESYS Control runtime systems, has a Buffer Overflow. CVSS 3.1CRITICAL 9.8
  • TI-2017-03937 Unrestricted file upload in 3S-Smart Software Solutions GmbH CODESYS Web Server CVSS 3.0CRITICAL 9.8
See all 155 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences