What’s Vulnerable › Vulnerabilities

CVE-2021-21777

• Severity: critical (CVSS 10.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-06-17 · updated 2026-06-17
• Weakness: CWE-125

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.

Affected products

• EIPStackGroup OpENer EtherNet/IP: 2.3

References

• https://talosintelligence.com/vulnerability_reports/TALOS-2021-1234
• https://talosintelligence.com/vulnerability_reports/TALOS-2021-1234

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