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CVE Record

CVE-2021-42384: A use-after-free in Busybox's awk applet leads to denial of service and possibly code execution when proces...

A use-after-free in Busybox's awk applet leads to denial of service and possibly code execution when processing a crafted awk pattern in the handle_special function

HighCVSS 7.2Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

BusyBox includes a compact awk tool used in many Linux-based environments. This CVE is a memory-use bug that can crash awk and may allow code execution when it processes a specially crafted awk pattern. The sources do not show active exploitation.

Executive priority

Treat as high priority for embedded, appliance, and container estates that rely on BusyBox. It is not KEV-listed in the supplied data, so prioritize by exposure to untrusted awk input and vendor patch availability.

Technical view

CVE-2021-42384 is a CWE-416 use-after-free in BusyBox awk, specifically the handle_special function, triggered during crafted awk pattern processing. The CVSS 3.1 score is 7.2 with high privileges required and high confidentiality, integrity, and availability impact.

Likely exposure

Exposure is most likely where BusyBox awk is present in Linux distributions, firmware, appliances, or embedded systems and can process attacker-controlled awk input. The supplied sources identify BusyBox generally, plus Fedora, Debian LTS, and NetApp advisories, but do not enumerate all affected downstream products.

Exploitation context

The bundle does not include KEV listing or cited evidence of active exploitation. The CVSS vector indicates network reachability and low complexity, but high privileges are required, which reduces broad opportunistic risk while preserving concern for privileged automation or administration paths.

Researcher notes

The key evidence is a use-after-free in BusyBox awk handle_special. Source detail is limited to public advisories and research references; avoid assuming product impact beyond listed vendors. Validate downstream packaging because BusyBox is often bundled rather than installed visibly.

Mitigation direction

  • Apply BusyBox updates from your OS, firmware, or appliance vendor.
  • Prioritize Fedora, Debian LTS, and NetApp guidance where relevant.
  • Limit who can supply awk programs or patterns to BusyBox awk.
  • Rebuild container images and firmware bundles that embed vulnerable BusyBox.
  • Track vendor advisories for product-specific fixed versions.

Validation and detection

  • Inventory systems and images for BusyBox and the awk applet.
  • Compare installed BusyBox packages against vendor security advisories.
  • Check appliance and firmware SBOMs for embedded BusyBox copies.
  • Review privileged scripts or services that process external awk input.
  • Confirm patched packages are deployed after updates or rebuilds.
Prepared
Confidence
medium
Sources
8

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-416: Exact CWE lookup

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description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2021-42384 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
7.2 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/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
7Source 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
7.2CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H1.25.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.2High
CVSS 3.1 vector shape for CVE-2021-42384Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

CWE details

CWE-416

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