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CVE-2021-42142

29
FAUCET Score

CVE-2021-42142 describes a critical denial-of-service vulnerability in Contiki-NG tinyDTLS, specifically affecting versions up to master branch 53a0d97. This flaw allows remote attackers to disrupt DTLS server operations and cause false-positive packet drops by exploiting the server's mishandling of early use of large epoch numbers. With a CVSS score of 9.8 (CRITICAL), this vulnerability is easily exploitable over the network with low attack complexity, potentially leading to high impact on confidentiality, integrity, and availability. While there is no known active exploitation, public exploit code, or Metasploit/Nuclei modules, the vulnerability has garnered significant community discussion with 10 mentions, indicating awareness within the cybersecurity community.

Impacted Technologies

VendorProductVersion(s)CPE
<= 2018-08-30CPE matchmatch criteria
cpe:2.3:a:contiki-ng:tinydtls:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.99%
Probability of exploitation in next 30 days
EPSS Percentile
58.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0099 is in the 44th percentile among its peer group of 36,833 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

seclists.org / fulldisclosure/2024/Jan/15
github.com / contiki-ng/tinydtls/issues/24
Issue TrackingPatch
seclists.org / fulldisclosure/2024/Jan/15
Mailing ListThird Party Advisory