CVE-2021-34566

CRITICALNVD 9.19.1—Trending — 3 sources updated this week

9.1

In WAGO I/O-Check Service in multiple products an unauthenticated remote attacker can send a specially crafted packet containing OS commands to crash the iocheck process and write memory resulting in loss of integrity and DoS.

CVSS v3: 9.1
EG Score: 9.1(medium)
EPSS: 76.0%
KEV: Not listed

Published

November 9, 2022

Last Modified

November 21, 2024

References (2)

info@certhttps://cert.vde.com/en/advisories/VDE-2020-036/
af854a3a-2127-422b-91ae-364da2661108https://cert.vde.com/en/advisories/VDE-2020-036/

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-120Buffer Copy without Checking Size (Classic Buffer Overflow)

Data Freshness Timeline

(refreshed 11× in last 7d / 11× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-25 12:26 UTCEG score recompute
2026-05-25 12:26 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2021-34566?

CVE-2021-34566 is a critical vulnerability published on November 9, 2022. In WAGO I/O-Check Service in multiple products an unauthenticated remote attacker can send a specially crafted packet containing OS commands to crash the iocheck process and write memory resulting in loss of integrity and DoS.

When was CVE-2021-34566 disclosed?

CVE-2021-34566 was first published in the National Vulnerability Database on November 9, 2022, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-34566 actively exploited?

CVE-2021-34566 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 76.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-34566?

CVE-2021-34566 has a CVSS v3 base score of 9.1 (NVD).

How do I remediate CVE-2021-34566?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-34566, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-34566

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CVE-2021-34566

📅 Published

🔄 Last Modified

🔗 References (2)