CVE-2021-21000

MEDIUMNVD 5.37.5▲

5.3

On WAGO PFC200 devices in different firmware versions with special crafted packets an attacker with network access to the device could cause a denial of service for the login service of the runtime.

CVSS v3: 5.3
EG Score: 7.5(medium)
EPSS: 36.7%
KEV: Not listed

Published

May 24, 2021

Last Modified

August 15, 2025

References (2)

info@certhttps://cert.vde.com/en-us/advisories/vde-2021-014
af854a3a-2127-422b-91ae-364da2661108https://cert.vde.com/en-us/advisories/vde-2021-014

Weakness Classification(1)

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

CWE-770Allocation of Resources Without Limits or Throttling

Data Freshness Timeline

(refreshed 11× in last 7d / 19× 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.

2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 16:14 UTCEG score recompute
2026-05-26 16:14 UTCGHSA enrichment
2026-05-26 13:42 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-24 16:49 UTCepss_batch

Frequently asked(5)

What is CVE-2021-21000?

CVE-2021-21000 is a medium vulnerability published on May 24, 2021. On WAGO PFC200 devices in different firmware versions with special crafted packets an attacker with network access to the device could cause a denial of service for the login service of the runtime.

When was CVE-2021-21000 disclosed?

CVE-2021-21000 was first published in the National Vulnerability Database on May 24, 2021, with the most recent update on August 15, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-21000 actively exploited?

CVE-2021-21000 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 36.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-21000?

CVE-2021-21000 has a CVSS v3 base score of 5.3 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 7.5.

How do I remediate CVE-2021-21000?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-21000, 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

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CVE-2021-21000

📅 Published

🔄 Last Modified

🔗 References (2)

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-21000?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (2)

Frequently asked(5)

Related CVEs(same CWE)