CVE-2021-42375
MEDIUMDescription
An incorrect handling of a special element in Busybox's ash applet leads to denial of service when processing a crafted shell command, due to the shell mistaking specific characters for reserved characters. This may be used for DoS under rare conditions of filtered command input.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 30% of all known CVEs.
References
Related Vulnerabilities
Other CWE-159 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2021-21707 | Medium | 5.3 | 26% | - | Fix |
| CVE-2019-9505 | Critical | 9.8 | 3.5% | - | - |
| CVE-2020-1653 | High | 7.5 | 1.6% | - | - |
| CVE-2020-1648 | High | 7.5 | 1.3% | - | - |
| CVE-2020-1646 | High | 7.5 | 1.0% | - | - |
| CVE-2020-29022 | Medium | 5.3 | 0.8% | - | Fix |
Common questions
How do I fix CVE-2021-42375?
Upgrade busybox on debian 12 to 1:1.35.0-1 or later.
Is CVE-2021-42375 being actively exploited?
Not that we know of. CVE-2021-42375 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.38% is the estimated probability that it will be exploited in the next 30 days. That is higher than 30% of all scored CVEs.
How severe is CVE-2021-42375?
CVE-2021-42375 has a CVSS v3 base score of 5.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-42375 affect?
Published advisories record a fix for busybox (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2021-42375
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-04-23.