dbcve.org
FedoraOperating system · Fedoraproject

CVE-2021-42385

HIGH · 7.2 CVSS v3.1 Published 2021-11-15
Fix available
A fix is available. Upgrade to after 1.33.1 or later.
See remediation →
78/100
Remediation priority · High
Remotely reachable Zero-click

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 · unedited
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 evaluate function

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 · high confidence

Use-after-free vulnerability in BusyBox's awk applet in the evaluate function when processing a crafted awk pattern, leading to denial of service and potential code execution.

MitigationUpdate BusyBox to a patched version that addresses this vulnerability, or avoid processing untrusted awk patterns until the update can be applied.

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
FedoraOperating system
Affected:= 33= 34
BusyboxApplication
Affected:>= 1.16.0, <= 1.33.1

CVSS 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
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Work through these to decide whether this CVE applies to you.

  1. Check if BusyBox is installed
    Run `busybox --version` or `busybox` alone to see if BusyBox is present on the system
    Affected if BusyBox is not installed or not in PATH - the system is not affected
  2. Identify the installed BusyBox version
    Run `busybox --version 2>&1 | head -1` and note the version number returned (format is typically like BusyBox X.XX.X)
    Affected if Version cannot be determined - further manual investigation required
  3. Verify awk applet is available
    Run `which awk` or `busybox awk --help` to confirm the awk applet is built and accessible
    Affected if The awk command is not available - the vulnerability cannot be triggered even with a vulnerable version
  4. Compare version against affected range
    Check if the installed version is >= 1.16.0 AND <= 1.33.1. For example, versions 1.16.0, 1.30.0, 1.33.1 are all within the affected range
    Affected if Version falls within >= 1.16.0 and <= 1.33.1 AND awk applet is available - the environment is affected by this CVE

The environment is affected if BusyBox version is between 1.16.0 and 1.33.1 inclusive AND the awk applet is enabled and accessible on the system.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to a release after 1.33.1
Interim mitigation

Update BusyBox to a patched version that addresses this vulnerability, or avoid processing untrusted awk patterns until the update can be applied.

Fix this in Fedora Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA4.0 h
40.0 hours of engineering $7,000
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $11,200.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-42385 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-42385 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data