CVE-2021-34570 json
Phoenix Contact: DoS for PLCnext Control devices in versions prior to 2021.0.5 LTS
published 2021-09-27 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-21220
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.0%
- EPSS 1.0% chance of exploitation in 30 days, percentile 62%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- Phoenix Contact AXC F 2021.0.5 LTS
- Phoenix Contact RFC 2021.0.5 LTS
- Phoenix Contact PLCnext 2021.0.5 LTS
Exploit prediction
0.98% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVD | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 7.8 | AV:N/AC:L/Au:N/C:N/I:N/A:C |
Affected products
- Phoenix Contact AXC F
- Phoenix Contact RFC
- Phoenix Contact PLCnext
Classification
- Weakness
-
- CWE-20 Improper Input Validation
References
-
cert.vde.com
/en/advisories/VDE-2021-029/
patch, third-party-advisory
Sources
- CVE List CVE-2021-34570
- NVD CVE-2021-34570
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.