CVE-2021-42147

CRITICALNVD 9.19.1—

9.1

Buffer over-read vulnerability in the dtls_sha256_update function in Contiki-NG tinyDTLS through master branch 53a0d97 allows remote attackers to cause a denial of service via crafted data packet.

CVSS v3: 9.1
EG Score: 9.1(medium)
EPSS: 58.0%
KEV: Not listed

Published

January 24, 2024

Last Modified

May 30, 2025

References (3)

cve@mitrehttps://seclists.org/fulldisclosure/2024/Jan/20
af854a3a-2127-422b-91ae-364da2661108http://seclists.org/fulldisclosure/2024/Jan/20
af854a3a-2127-422b-91ae-364da2661108https://seclists.org/fulldisclosure/2024/Jan/20

Weakness Classification(1)

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

CWE-125Out-of-bounds Read

Data Freshness Timeline

(refreshed 13× in last 7d / 20× 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.

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Frequently asked(5)

What is CVE-2021-42147?

CVE-2021-42147 is a critical vulnerability published on January 24, 2024. Buffer over-read vulnerability in the dtlssha256update function in Contiki-NG tinyDTLS through master branch 53a0d97 allows remote attackers to cause a denial of service via crafted data packet.

When was CVE-2021-42147 disclosed?

CVE-2021-42147 was first published in the National Vulnerability Database on January 24, 2024, with the most recent update on May 30, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-42147 actively exploited?

CVE-2021-42147 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 58.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-42147?

CVE-2021-42147 has a CVSS v3 base score of 9.1 (NVD).

How do I remediate CVE-2021-42147?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-42147, 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-2021-42147

📅 Published

🔄 Last Modified

🔗 References (3)

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-42147?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (3)

Frequently asked(5)

Related CVEs(same CWE)