CVE-2021-34570: Phoenixcontact Axc F 1152 Firmware

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

Multiple Phoenix Contact PLCnext control devices in versions prior to 2021.0.5 LTS are prone to a DoS attack through special crafted JSON requests.

Affected products

• Phoenixcontact Axc F 1152 Firmware: before 2021.0.5 (fixed in 2021.0.5)
• Phoenixcontact Axc F 2152 Firmware: before 2021.0.5 (fixed in 2021.0.5)
• Phoenixcontact Axc F 2152 Starterkit Firmware: before 2021.0.5 (fixed in 2021.0.5)
• Phoenixcontact Axc F 3152 Firmware: before 2021.0.5 (fixed in 2021.0.5)
• Phoenixcontact Plcnext Technology Starterkit Firmware: before 2021.0.5 (fixed in 2021.0.5)
• Phoenixcontact Rfc 4072s Firmware: before 2021.0.5 (fixed in 2021.0.5)

Published 2021-09-27. Last modified 2026-06-17.