CVE-2016-6831 in Scheme
Summary
by MITRE
The "process-execute" and "process-spawn" procedures did not free memory correctly when the execve() call failed, resulting in a memory leak. This could be abused by an attacker to cause resource exhaustion or a denial of service. This affects all releases of CHICKEN up to and including 4.11 (it will be fixed in 4.12 and 5.0, which are not yet released).
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Analysis
by VulDB Data Team • 04/20/2025
The vulnerability identified as CVE-2016-6831 resides within the CHICKEN Scheme implementation and represents a classic memory management flaw that can be exploited to undermine system stability. This issue specifically impacts the process execution and spawning mechanisms within the software, where improper memory deallocation occurs during failure conditions of the execve() system call. The flaw exists in the core runtime behavior of CHICKEN, affecting versions through 4.11, and demonstrates a fundamental weakness in resource cleanup procedures that should be automatically handled by the system.
The technical root cause of this vulnerability stems from the improper handling of memory allocation and deallocation within the process execution pathways. When the execve() system call fails, the memory allocated for process execution contexts is not properly freed, leading to gradual memory accumulation over time. This memory leak occurs because the implementation does not properly account for error conditions in the execution flow, specifically failing to invoke cleanup routines when execve() returns an error status. The vulnerability manifests as a progressive consumption of available memory resources, which can eventually lead to system instability or complete resource exhaustion.
From an operational perspective, this vulnerability presents a significant risk for systems relying on CHICKEN for process management and execution tasks. Attackers can exploit this weakness by repeatedly invoking process execution procedures that are designed to fail, thereby gradually consuming system memory resources until the system becomes unresponsive or crashes. The impact extends beyond simple denial of service as the memory exhaustion can affect other applications running on the same system, potentially causing cascading failures. This vulnerability particularly affects server environments where CHICKEN is used for automated task execution or web application processing, where sustained exploitation could lead to complete service disruption.
The vulnerability aligns with CWE-401, which specifically addresses improper cleanup of memory resources, and demonstrates characteristics consistent with the ATT&CK technique T1499.1, involving resource exhaustion through memory leaks. Organizations using CHICKEN versions 4.11 or earlier should prioritize immediate mitigation through patching to version 4.12 or 5.0, as these releases contain the necessary memory management fixes. Additionally, system administrators should implement monitoring for unusual memory consumption patterns in processes utilizing CHICKEN, as early detection can help identify exploitation attempts. The fix implemented in newer versions ensures proper error handling and memory cleanup during execve() failures, addressing the underlying memory management issue at its source.