Busybox
CVE-2021-42376
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A10:2025 - Mishandling of Exceptional Conditions
ASVS 5.0
V16 - Security Logging and Error Handling Null pointer safety, defensive checks
MITRE ATT&CK
1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 5.5 (MEDIUM). Attack characteristics: local attack vector, low complexity, low privileges required, no user interaction not required. |
| Exploit ScenarioDerived | A local attacker with access to the system could crash the application by dereferencing a null pointer. |
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Alert meAnalysisAI
A NULL pointer dereference in Busybox's hush applet leads to denial of service when processing a crafted shell command, due to missing validation after a \x03 delimiter character. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Check pointers before dereferencing. Use static analysis tools to detect null pointer paths.
Affects your stack
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Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as NULL Pointer Dereference (CWE-476), which allows attackers to crash the application by dereferencing a null pointer. A NULL pointer dereference in Busybox's hush applet leads to denial of service when processing a crafted shell command, due to missing validation after a \x03 delimiter character. This may be used for DoS under very rare conditions of filtered command input. Affected products include: Busybox, Fedoraproject Fedora, Netapp Cloud Backup, Netapp Hci Management Node, Netapp Solidfire.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
A NULL pointer dereference in Busybox's hush applet leads to denial of service when processing a crafted shell command, due to missing validation after a \x03 delimiter character. This may be used for DoS under very rare conditions of filtered command input.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A null pointer dereference occurs when a program attempts to access memory through a pointer that has been set to NULL (address 0x0).
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)NVD
Heap-based buffer overflow in the DHCP client (udhcpc) in BusyBox before 1.25.0 allows remote attackers to have unspecif
In the add_match function in libbb/lineedit.c in BusyBox through 1.27.2, the tab autocomplete feature of the shell, used
Integer overflow in the DHCP client (udhcpc) in BusyBox before 1.25.0 allows remote attackers to cause a denial of servi
BusyBox through 1.35.0 allows remote attackers to execute arbitrary code if netstat is used to print a DNS PTR record's
BusyBox wget thru 1.3.7 accepted raw CR (0x0D)/LF (0x0A) and other C0 control bytes in the HTTP request-target (path/que
A use-after-free in Busybox 1.35-x's awk applet leads to denial of service and possibly code execution when processing a
An issue was discovered in BusyBox through 1.30.0. Rated high severity (CVSS 7.5), this vulnerability is remotely exploi
util-linux/mdev.c in BusyBox before 1.21.0 uses 0777 permissions for parent directories when creating nested directories
Network-reachable BLU-IC2 and BLU-IC4 devices running firmware through 1.19.5 embed BusyBox 1.31.1 and are exposed to mu
An attacker-controlled pointer free in Busybox's hush applet leads to denial of service and possible code execution when
BusyBox project BusyBox wget version prior to commit 8e2174e9bd836e53c8b9c6e00d1bc6e2a718686e contains a Buffer Overflow
A heap-buffer-overflow was discovered in BusyBox v.1.36.1 in the next_token function at awk.c:1159. Rated medium severit
GitHub PoC
Exploit-DB