Security readout for executives and security teams
Plain-English summary
BusyBox ash can mishandle certain special characters in a crafted shell command and crash or deny service. This is not described as remote code execution or data theft. Business urgency is highest where BusyBox backs operational scripts, restricted shells, appliances, or systems where a local user can submit filtered command input.
Executive priority
Handle through normal vulnerability management, with higher priority for operational systems where local users or restricted interfaces can trigger BusyBox ash. There is no sourced evidence of active exploitation in the provided bundle.
Technical view
CVE-2021-42375 affects BusyBox's ash applet. The CVSS vector is local, low complexity, low privileges, no user interaction, unchanged scope, and high availability impact. The provided record lists unspecified BusyBox versions and describes denial of service under rare filtered-command-input conditions.
Likely exposure
Exposure depends on whether BusyBox ash is installed and whether local or constrained command input reaches it. The bundle does not provide exact affected versions, so validate through package data, SBOMs, firmware inventories, and vendor advisories.
Exploitation context
The source bundle does not show CISA KEV listing or cited active exploitation. Exploitation requires local low-privileged access or a pathway that passes crafted shell input to BusyBox ash under specific filtered-input conditions.
Researcher notes
Evidence is strongest for vulnerability class, impact, and CVSS characteristics. Version specificity is incomplete: affected versions are listed as unspecified. Avoid broad product claims beyond BusyBox and cited vendor advisories; use advisory-driven validation for downstream distributions and appliances.
Mitigation direction
- Check BusyBox vendor and distribution advisories for fixed package versions.
- Prioritize updates where ash processes user-controlled or filtered command input.
- Use Fedora or product-vendor advisories to identify corrected packages.
- Reduce local shell access and command-submission paths where practical.
- Track appliance vendors such as NetApp for product-specific guidance.
Validation and detection
- Inventory systems, containers, and firmware images that include BusyBox.
- Confirm whether the BusyBox ash applet is present and enabled.
- Map installed BusyBox versions against vendor advisory status.
- Review restricted shells or wrappers that pass filtered input to ash.
- Document exceptions where vendor 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-159: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-42375 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
- Medium
- CVSS
- 5.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.5MediumVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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
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.
Improper Handling of Invalid Use of Special Elements
Improper Handling of Invalid Use of Special Elements represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.