CVE-2021-20987
CWE-787Published: February 16, 2021· Updated: Jun 17, 2026
Official Description
A denial of service and memory corruption vulnerability was found in Hilscher EtherNet/IP Core V2 prior to V2.13.0.21that may lead to code injection through network or make devices crash without recovery.
Technical Analysis
CVE-2021-20987 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 8.6.
The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.
From a weakness classification perspective (CWE-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (4)
Quick Facts
Related CVEs (CWE-787)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-20987 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts