No exploitation reportedFix available

CVE-2021-20987

Q: Is CVE-2021-20987 actively exploited?

Active exploitation of CVE-2021-20987 has not been confirmed. Its EPSS score was 1.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-20987?

CVE-2021-20987 has a CVSS v3 base score of 8.6 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.

No exploitation reported by the sources we read.

Published2021-02-16
Fixed in2.13.0.21
WeaknessCWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC

2021-02-1617:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-20987?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-20987?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Hilscher ethernet\/ip adapter firmwareversion to verify

Branch	Affected	Fixed in	Source
2.x	≥ 2.0, < 2.13.0.21	2.13.0.21	NVD

Pepperl-fuchs pcv100-f200-b25-v1d-6011 firmwareversion to verify

Branch	Affected	Fixed in	Source
1.10	≤ 1.10.0	no fix published	NVD

Pepperl-fuchs pcv100-f200-b25-v1d-6011-6720 firmwareversion to verify

Branch	Affected	Fixed in	Source
1.10	≤ 1.10.0	no fix published	NVD

5 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Hilscher ethernet\/ip adapter firmware to 2.13.0.21

Advisories and patches

kb.hilscher.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CNACVSS 3.18.6read 2026-10-23
NVDCVSS 3.18.6read 2026-10-23
NVDCVSS 2.07.8read 2026-10-23
CNAweakness (CWE)CWE-787read 2026-10-23
NVDweakness (CWE)CWE-787read 2026-10-23
FIRST EPSSEPSS score1.1 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Published: 2021-02-16
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-20987?

Is CVE-2021-20987 actively exploited?

Active exploitation of CVE-2021-20987 has not been confirmed. Its EPSS score was 1.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-20987?

CVE-2021-20987 has a CVSS v3 base score of 8.6 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.

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