CVE-2021-21777
CVSS v3
10
CRITICAL
EPSS Score
1.7 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
An information disclosure vulnerability exists in the Ethernet/IP UDP handler functionality of EIP Stack Group OpENer 2.3 and development commit 8c73bf3. A specially crafted network request can lead to an out-of-bounds read.
Technical details
- Published
- 2021-06-17
Frequently asked questions
What is CVE-2021-21777?
An information disclosure vulnerability exists in the Ethernet/IP UDP handler functionality of EIP Stack Group OpENer 2.3 and development commit 8c73bf3. A specially crafted network request can lead to an out-of-bounds read.
Is CVE-2021-21777 actively exploited?
Active exploitation of CVE-2021-21777 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-2021-21777?
CVE-2021-21777 has a CVSS v3 base score of 10 (CRITICAL severity).
Is CVE-2021-21777 affecting your environment?
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