How severe is CVE-2021-42146?

CVE-2021-42146 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-42146 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-42146?

CVE-2021-42146 affects Contiki-ng Tinydtls. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-42146?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2021-42146 have an EU (EUVD) identifier?

Yes. CVE-2021-42146 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-29129.

When was CVE-2021-42146 published?

CVE-2021-42146 was published on 2024-01-24 and last updated on 2026-06-17.

CVE-2021-42146

CVE-2021-42146 is a high-severity vulnerability in Contiki-ng Tinydtls with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-755.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (47th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2021-29129
Weakness: CWE-755
Affected product: Contiki-ng Tinydtls
Published: 2024-01-24
Last modified: 2026-06-17

Description

An issue was discovered in Contiki-NG tinyDTLS through master branch 53a0d97. DTLS servers allow remote attackers to reuse the same epoch number within two times the TCP maximum segment lifetime, which is prohibited in RFC6347. This vulnerability allows remote attackers to obtain sensitive application (data of connected clients).

Frequently asked questions

What is CVE-2021-42146?: An issue was discovered in Contiki-NG tinyDTLS through master branch 53a0d97. DTLS servers allow remote attackers to reuse the same epoch number within two times the TCP maximum segment lifetime, which is prohibited in RFC6347. This vulnerability allows remote attackers to obtain sensitive application (data of connected clients).
How severe is CVE-2021-42146?: CVE-2021-42146 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-42146 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-42146?: CVE-2021-42146 affects Contiki-ng Tinydtls. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-42146?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2021-42146 have an EU (EUVD) identifier?: Yes. CVE-2021-42146 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-29129.
When was CVE-2021-42146 published?: CVE-2021-42146 was published on 2024-01-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:contiki-ng:tinydtls:2018-08-30:*:*:*:*:*:*:*

More vulnerabilities in Contiki-ng Tinydtls

CVE-2021-42142 — Critical (CVSS 9.8): An issue was discovered in Contiki-NG tinyDTLS through master branch 53a0d97. DTLS servers mishandle the early use of a…
CVE-2021-42141 — Critical (CVSS 9.8): An issue was discovered in Contiki-NG tinyDTLS through 2018-08-30. One incorrect handshake could complete with…
CVE-2021-42147 — Critical (CVSS 9.1): Buffer over-read vulnerability in the dtls_sha256_update function in Contiki-NG tinyDTLS through master branch 53a0d97…
CVE-2021-42143 — Critical (CVSS 9.1): An issue was discovered in Contiki-NG tinyDTLS through master branch 53a0d97. An infinite loop bug exists during the…
CVE-2021-42145 — High (CVSS 7.5): An assertion failure discovered in in check_certificate_request() in Contiki-NG tinyDTLS through master branch 53a0d97…

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CVE-2021-42142 — Critical (CVSS 9.8): An issue was discovered in Contiki-NG tinyDTLS through master branch 53a0d97. DTLS servers mishandle the early use of a…
CVE-2021-42141 — Critical (CVSS 9.8): An issue was discovered in Contiki-NG tinyDTLS through 2018-08-30. One incorrect handshake could complete with…
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