Security readout for executives and security teams
Plain-English summary
BusyBox is widely embedded in Linux-based devices and appliances. This flaw is in its awk applet: a specially crafted awk pattern can trigger memory misuse, causing denial of service and possibly code execution. Business risk depends on whether systems expose BusyBox awk to untrusted input.
Executive priority
Prioritize remediation for embedded devices, appliances, and containers that rely on BusyBox and accept administrative or automated input. This is high severity, but urgency is lower than known-exploited issues because active exploitation is not evidenced in the provided sources.
Technical view
CVE-2021-42380 is a CWE-416 use-after-free in BusyBox awk's clrvar function when processing a crafted awk pattern. The supplied CVSS v3.1 score is 7.2 with high confidentiality, integrity, and availability impact, but high privileges required. Affected BusyBox versions are not specified in the bundle.
Likely exposure
Most relevant exposure is embedded Linux, network appliances, containers, or distributions shipping BusyBox with awk enabled. Practical exposure requires a path for attackers or high-privileged users to supply crafted awk patterns. Fedora, Debian LTS, and NetApp references indicate downstream product impact.
Exploitation context
The bundle does not show CISA KEV listing or active exploitation evidence. Public research states the issue can cause denial of service and possibly code execution, but the supplied CVSS vector requires high privileges. Treat exploitation status as unconfirmed.
Researcher notes
Key uncertainty is affected-version scope: the bundle lists BusyBox versions as unspecified. Researchers should avoid assuming universal exploitability and instead validate awk availability, input paths, privilege context, and downstream vendor patch status. Do not infer active exploitation from the research publication alone.
Mitigation direction
- Update BusyBox through the operating system, firmware, or vendor-supported package channel.
- Apply relevant downstream advisories for Fedora, Debian LTS, NetApp, or device vendors.
- Reduce or remove workflows that process untrusted awk patterns with BusyBox awk.
- For appliances, check vendor firmware guidance before assuming package-level fixes apply.
- Prioritize systems where BusyBox awk is reachable from administrative or automation interfaces.
Validation and detection
- Inventory assets running BusyBox and record package, firmware, or image versions.
- Confirm whether the BusyBox awk applet is present and used in exposed workflows.
- Map affected assets to vendor advisories and installed update levels.
- Review automation, scripts, and management interfaces for untrusted awk pattern handling.
- Document exceptions where vendor affected-version data is unavailable.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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-416: 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.
Open ATT&CK lookupExecution 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.
Open ATT&CK lookupCVE-2021-42380 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- 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
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.
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H1.25.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.2HighVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://jfrog.com/blog/unboxing-busybox-14-new-vulnerabilities-uncovered-by-claroty-and-jfrog/CVE reference
- FEDORA-2021-5a95823596CVE reference · vendor-advisory
- FEDORA-2021-c52c0fe490CVE reference · vendor-advisory
- https://security.netapp.com/advisory/ntap-20211223-0002/CVE reference
- https://claroty.com/team82/research/unboxing-busybox-14-vulnerabilities-uncovered-by-claroty-jfrogCVE reference
- https://lists.debian.org/debian-lts-announce/2025/01/msg00012.htmlCVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.