CVE-2026-38752 in BusyBox
Summary
by MITRE • 07/16/2026
A stack overflow in the evaluate() function (editors/awk.c) of BusyBox commit 371fe9 allows attackers to cause a Denial of Service (DoS) via supplying a crafted AWK script.
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Analysis
by VulDB Data Team • 07/16/2026
The vulnerability resides within the busybox implementation of the awk command processor where the evaluate() function in editors/awk.c lacks proper input validation and stack management. This flaw represents a classic stack buffer overflow condition that occurs when processing maliciously crafted AWK scripts, allowing attackers to manipulate the program execution flow through excessive stack consumption. The issue stems from insufficient bounds checking during script evaluation, particularly when handling complex nested expressions or recursive patterns that exceed the allocated stack space.
The technical implementation of this vulnerability demonstrates how the AWK interpreter fails to enforce stack depth limitations during expression evaluation, creating a condition where attacker-controlled input can trigger unbounded recursion or excessive memory allocation within the function call stack. This behavior aligns with CWE-121 Stack-based Buffer Overflow, which specifically addresses vulnerabilities arising from improper handling of stack memory operations in programming environments. The flaw operates at the intersection of software security and interpreted language processing, where the dynamic nature of AWK script execution creates opportunities for attackers to craft inputs that exploit memory management weaknesses inherent in the busybox implementation.
Operationally this vulnerability presents a significant denial of service risk to systems running vulnerable versions of busybox, particularly in embedded environments or network appliances where awk functionality is commonly utilized. The impact extends beyond simple service interruption as the overflow can potentially lead to program termination or system instability when the stack overflow occurs during critical script processing operations. Attackers can exploit this through carefully constructed AWK scripts that cause the evaluate() function to recurse indefinitely or consume excessive stack resources, making it particularly dangerous in environments where automated script processing occurs or where users can submit arbitrary AWK content.
Mitigation strategies should focus on implementing proper input validation and stack depth monitoring within the awk interpreter implementation. System administrators should prioritize updating to patched versions of busybox that address the specific stack overflow conditions in the evaluate() function, while also implementing runtime protections such as stack canaries or memory protection mechanisms. The vulnerability highlights the importance of applying security patches promptly and maintaining updated software versions in embedded systems where busybox components are prevalent. Additionally, network segmentation and access controls should be implemented to limit exposure of systems running vulnerable awk implementations, particularly in environments where untrusted input processing occurs. Organizations should also consider implementing intrusion detection systems that monitor for suspicious AWK script execution patterns that could indicate exploitation attempts.
This vulnerability type falls under the ATT&CK technique T1499.004 for Network Denial of Service and demonstrates how interpreted language processors can create attack surfaces when proper memory management controls are absent. The flaw represents a fundamental security weakness in embedded system software development practices where resource constraints often lead to insufficient input validation and error handling mechanisms.