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CVE-2021-20987: A denial of service and memory corruption vulnerability was found in Hilscher EtherNet/IP Core V2 prior to V2.

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HIGH 8.6REMOTEUPGRADEUPGRADEUPGRADE

CVE-2021-20987 is a high-severity flaw (CVSS 8.6) affecting ethernet\/ip adapter firmware, wcs firmware, pxv100-f200-b25-v1d firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

  • High severity
  • Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score8.6 (High)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance1.1% (top 33%)
CISA exploited listNo
WeaknessCWE-787
Published2021-02-16
Last modified2026-06-17
Publisher (CNA): CERT VDE · Vendor: hilscher · pepperl-fuchs

Share: LinkedIn · X · Reddit

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

hilscher ethernet\/ip adapter firmware UPGRADE
Affected: >= 2.0 and < 2.13.0.21
Fixed in: 2.13.0.21
Safe to downgrade to: a release before 2.0
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
pepperl-fuchs wcs firmware UPGRADE
Affected: <= 1.2.1
Fixed in: newer than 1.2.1
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
pepperl-fuchs pxv100-f200-b25-v1d firmware UPGRADE
Affected: <= 1.10.0
Fixed in: newer than 1.10.0
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
pepperl-fuchs pxv100i-f200-b25-v1d firmware UPGRADE
Affected: <= 1.10.0
Fixed in: newer than 1.10.0
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
pepperl-fuchs pcv100-f200-b25-v1d-6011-6720 firmware UPGRADE
Affected: <= 1.10.0
Fixed in: newer than 1.10.0
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
pepperl-fuchs pcv50-f200-b25-v1d firmware UPGRADE
Affected: <= 1.10.0
Fixed in: newer than 1.10.0
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-20987?

ethernet\/ip adapter firmware: upgrade to 2.13.0.21; wcs firmware: upgrade to newer than 1.2.1; pxv100-f200-b25-v1d firmware: upgrade to newer than 1.10.0. Exact commands for each OS are on this page.

Is CVE-2021-20987 being exploited?

CVE-2021-20987 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-20987 affect?

CVE-2021-20987 affects ethernet\/ip adapter firmware, wcs firmware, pxv100-f200-b25-v1d firmware. Severity is high (CVSS 8.6). 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.

How urgent is CVE-2021-20987?

Priority 52/100. High severity; Remotely exploitable, no login, no user action

References

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