CVE-2021-21002: Phoenixcontact Fl Comserver Uni 232/422/485-T Firmware

High severity, CVSS 7.5. EPSS: 1% chance of exploitation in the next 30 days.

In Phoenix Contact FL COMSERVER UNI in versions < 2.40 a invalid Modbus exception response can lead to a temporary denial of service.

Affected products

• Phoenixcontact Fl Comserver Uni 232/422/485-T Firmware: before 2.40 (fixed in 2.40)
• Phoenixcontact Fl Comserver Uni 232/422/485 Firmware: before 2.40 (fixed in 2.40)

Published 2021-06-25. Last modified 2026-06-17.