CVE-2023-42364 in BusyBox
Summary
by MITRE • 11/28/2023
A use-after-free vulnerability in BusyBox v.1.36.1 allows attackers to cause a denial of service via a crafted awk pattern in the awk.c evaluate function.
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Analysis
by VulDB Data Team • 02/02/2026
The vulnerability identified as CVE-2023-42364 represents a critical use-after-free condition within BusyBox version 1.36.1 that specifically impacts the awk utility's evaluation function in awk.c. This flaw arises from improper memory management during the processing of crafted awk patterns, creating a scenario where freed memory regions are accessed or reused by subsequent operations. The vulnerability is particularly concerning as it affects a widely deployed system utility that serves as a foundational component in numerous embedded systems, Linux distributions, and containerized environments where BusyBox is commonly utilized.
The technical implementation of this vulnerability occurs within the awk.c source file where the evaluate function fails to properly manage memory references after certain pattern processing operations. When an attacker provides a maliciously crafted awk pattern, the function executes code paths that lead to memory deallocation followed by subsequent access to the same memory locations, creating a use-after-free condition. This memory corruption can manifest through various execution contexts including shell environments, automated scripts, and system services that invoke awk functionality. The flaw demonstrates characteristics consistent with CWE-416, which specifically addresses use-after-free vulnerabilities where memory is accessed after it has been freed, making it a direct implementation of this well-known weakness category.
The operational impact of CVE-2023-42364 extends beyond simple denial of service to potentially enable more sophisticated attack vectors. While the primary effect is a system denial of service through process crashes or system instability, the underlying memory corruption could theoretically be exploited to achieve arbitrary code execution under certain conditions. The vulnerability affects systems where awk is invoked with user-controlled input, particularly in environments where BusyBox serves as the standard implementation of core utilities. This includes embedded devices, IoT systems, containerized applications, and various Linux-based platforms where BusyBox is the default utility suite, making the attack surface particularly broad and impactful.
Mitigation strategies for CVE-2023-42364 should prioritize immediate patching of affected BusyBox installations to version 1.36.2 or later, which contains the necessary memory management fixes. System administrators should implement input validation measures to prevent untrusted awk patterns from being processed, particularly in contexts where user input is accepted. Network segmentation and privilege separation can help limit the potential impact of exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.006 for command and scripting interpreter usage, and T1499.004 for network denial of service, highlighting the need for comprehensive defensive measures. Organizations should also conduct vulnerability assessments to identify all systems running affected BusyBox versions and establish monitoring protocols to detect potential exploitation attempts, particularly in environments where awk is frequently used with external input sources.