CVE-2021-21864
CVSS v3
7.8
HIGH
EPSS Score
1.7 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
A unsafe deserialization vulnerability exists in the ComponentModel ComponentManager.StartupCultureSettings functionality of CODESYS GmbH CODESYS Development System 3.5.16 and 3.5.17. A specially crafted file can lead to arbitrary command execution. An attacker can provide a malicious file to trigger this vulnerability.
Technical details
- Published
- 2021-08-02
Frequently asked questions
What is CVE-2021-21864?
A unsafe deserialization vulnerability exists in the ComponentModel ComponentManager.StartupCultureSettings functionality of CODESYS GmbH CODESYS Development System 3.5.16 and 3.5.17. A specially crafted file can lead to arbitrary command execution. An attacker can provide a malicious file to trigger this vulnerability.
Is CVE-2021-21864 actively exploited?
Active exploitation of CVE-2021-21864 has not been confirmed. Its EPSS score was 1.7% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-21864?
CVE-2021-21864 has a CVSS v3 base score of 7.8 (HIGH severity).
Is CVE-2021-21864 affecting your environment?
Use isMalicious to check if any of your IPs or domains are associated with this vulnerability's IOCs.
No credit card required · 500 free checks/month · Free API key
Other 2021 vulnerabilities worth triaging
Ranked by exploit probability (EPSS).