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CVE Record

CVE-2021-42145: An assertion failure discovered in in check_certificate_request() in Contiki-NG tinyDTLS through master bra...

An assertion failure discovered in in check_certificate_request() in Contiki-NG tinyDTLS through master branch 53a0d97 allows attackers to cause a denial of service.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2021-42145 is a denial-of-service issue in Contiki-NG tinyDTLS. A network attacker can trigger an assertion failure, potentially crashing affected DTLS handling and disrupting availability. The public record does not provide CPEs, packaged versions, or a named patch.

Executive priority

Treat as high priority for products where DTLS is network reachable, especially internet-facing or operational technology deployments. Business risk is service interruption, not data theft, based on the supplied evidence.

Technical view

The issue is an assertion failure in check_certificate_request() in Contiki-NG tinyDTLS through master branch 53a0d97. CVSS 3.1 is 7.5: network reachable, low complexity, no privileges, no user interaction, availability impact only. CWE is CWE-755.

Likely exposure

Most relevant exposure is embedded, IoT, or networked products that include Contiki-NG tinyDTLS code from the affected master branch or derivatives. Public metadata does not enumerate affected vendors, CPEs, firmware versions, or downstream products.

Exploitation context

The CVE record supports unauthenticated network-triggered denial of service. It is not listed in KEV, and the supplied sources do not state active exploitation in the wild.

Researcher notes

The record is sparse: affected vendor/product fields are n/a, and no fix is named in the provided sources. Analysis should focus on code provenance, downstream embedding, reachability, and availability monitoring rather than assumed product lists.

Mitigation direction

  • Inventory products and firmware that embed Contiki-NG tinyDTLS.
  • Check Contiki-NG tinyDTLS vendor guidance for a fixed revision or advisory.
  • Reduce DTLS endpoint exposure to trusted networks where operationally feasible.
  • Monitor affected services for crash loops or availability degradation.
  • Prioritize fixes where DTLS is internet reachable or safety critical.

Validation and detection

  • Confirm whether deployed code includes tinyDTLS check_certificate_request().
  • Map embedded tinyDTLS code to master branch 53a0d97 or derivatives.
  • Identify externally reachable services using the affected DTLS component.
  • Review logs and crash reports for assertion-failure availability events.
  • Document unknown downstream versions for vendor follow-up.
Prepared
Confidence
medium
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-755: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2021-42145 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2021-42145Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

CWE-755

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-755 · source CWE mapping

Improper Handling of Exceptional Conditions

Improper Handling of Exceptional Conditions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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