CVE-2021-42145
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn assertion failure discovered in in check_certificate_request() in Contiki-NG tinyDTLS through master branch 53a0d97 allows attackers to cause a denial of service.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceAn assertion failure in check_certificate_request() in Contiki-NG tinyDTLS allows remote attackers to cause denial of service by sending specially crafted DTLS certificate request messages that trigger the assertion. The vulnerability is network-exploitable with no authentication required.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 2018-08-30CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify if Contiki-NG tinyDTLS is in useInspect the codebase or firmware to confirm the presence of the tinyDTLS library. Look for the tinydtls directory in the Contiki-NG source tree or embedded firmware image.Affected if tinyDTLS is present in the deployment
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Determine tinyDTLS or Contiki-NG versionCheck the version date of the Contiki-NG release or the tinyDTLS library build. Compare against the vulnerable cutoff of 2018-08-30.Affected if The version date is 2018-08-30 or earlier, or the build predates the fix commit 53a0d97
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Verify DTLS is enabled in the configurationInspect the project configuration (for example, Makefile or config files) for DTLS-related build flags such as DTLS_CONF_ENABLED or similar. Confirm the DTLS module is included in the build.Affected if DTLS support is compiled into the firmware or application
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Confirm DTLS server role is in useExamine the application code to determine if the device acts as a DTLS server (responds to DTLS client hello messages and processes certificate request messages). Check for DTLS server initialization or listening on DTLS ports.Affected if The device functions as a DTLS server and handles DTLS handshake messages including certificate requests
A user is affected if the deployment uses Contiki-NG with tinyDTLS built from code dated on or before 2018-08-30, has DTLS enabled, and the device operates as a DTLS server that processes incoming certificate request messages.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpdate tinyDTLS to a version past the vulnerable commit (53a0d97) that fixes the certificate request validation logic. If no update is available, consider network-level filtering of DTLS traffic or upgrading to a fixed Contiki-NG release.
- Consultation4.0 h
- Implementation8.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-42145 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-42145 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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