CVE-2023-51440: Siemens SIMATIC CP 343-1 Firmware

High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 30 days.

A vulnerability has been identified in SIMATIC CP 343-1 (6GK7343-1EX30-0XE0) (All versions), SIMATIC CP 343-1 Lean (6GK7343-1CX10-0XE0) (All versions), SIPLUS NET CP 343-1 (6AG1343-1EX30-7XE0) (All versions), SIPLUS NET CP 343-1 Lean (6AG1343-1CX10-2XE0) (All versions). Affected products incorrectly validate TCP sequence numbers. This could allow an unauthenticated remote attacker to create a denial of service condition by injecting spoofed TCP RST packets.

Affected products

• Siemens SIMATIC CP 343-1 Firmware: any version
• Siemens SIMATIC CP 343-1 Lean Firmware: affected versions not specified
• Siemens Siplus Net CP 343-1 Firmware: affected versions not specified
• Siemens Siplus Net CP 343-1 Lean Firmware: affected versions not specified

Published 2024-02-13. Last modified 2026-06-17.