CVE-2021-34570
Phoenix Contact: DoS for PLCnext Control devices in versions prior to 2021.0.5 LTS
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Phoenix Contact: DoS for PLCnext Control devices in versions prior to 2021.0.5 LTS
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.
- Record
CVE-2021-34570- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2021-21220
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.
- Record
EUVD-2021-21220- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-5jgp-38vj-293v
Multiple Phoenix Contact PLCnext control devices in versions prior to 2021.0.5 LTS are prone to a...
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.
- Record
GHSA-5jgp-38vj-293v- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-34570- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 7.8 High
AV:N/AC:L/Au:N/C:N/I:N/A:C - Weakness
- CWE-20
- Updated
- 2026-11-02
Affected products
- phoenix contact plcnext
- phoenix contact axc f
- phoenix contact rfc
- ietf rfc
- phoenixcontact axc f 1152 firmware
- phoenixcontact axc f 2152 firmware
- phoenixcontact axc f 2152 starterkit firmware
- phoenixcontact axc f 3152 firmware
- phoenixcontact plcnext technology starterkit firmware
- phoenixcontact rfc 4072s firmware
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, products, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-34570 is a high vulnerability (CVSS 7.5) in Phoenix Contact Plcnext, published September 27, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.98%, the 62nd percentile. No source names a fixed version.