CVE-2006-5656 in Vilistextum
Summary
by MITRE
Memory leak in the push_align function in src/util.c in Vilistextum before 2.6.9 allows remote attackers to cause a denial of service (memory consumption) via unspecified vectors related to the tmp_align variable. NOTE: it is not clear whether this is a vulnerability, due to the functionality of the product.
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Analysis
by VulDB Data Team • 04/26/2026
The vulnerability identified as CVE-2006-5656 affects Vilistextum versions prior to 2.6.9, specifically within the push_align function located in src/util.c. This memory leak occurs when processing the tmp_align variable, creating a condition where allocated memory is not properly released during program execution. The issue represents a classic memory management flaw that can lead to progressive resource exhaustion over time.
The technical implementation of this vulnerability stems from improper memory deallocation within the push_align function, which is part of Vilistextum's text processing utilities. When the tmp_align variable is manipulated during text alignment operations, the function fails to correctly free previously allocated memory blocks. This type of memory leak falls under CWE-401, which specifically addresses memory leaks in software systems. The vulnerability manifests when remote attackers can trigger the affected code path through unspecified vectors, potentially causing progressive memory consumption that degrades system performance.
From an operational perspective, this vulnerability creates a significant denial of service risk for systems running affected versions of Vilistextum. The memory leak can accumulate over time, eventually leading to system instability or complete service unavailability. Attackers can exploit this weakness by sending carefully crafted inputs that trigger the push_align function repeatedly, causing the application to consume increasing amounts of memory until system resources are exhausted. This behavior aligns with ATT&CK technique T1499.001, which covers resource exhaustion attacks targeting memory consumption.
The impact of this vulnerability extends beyond simple service disruption, as it can affect system availability and potentially compromise the overall stability of applications that depend on Vilistextum for text processing operations. The uncertainty surrounding whether this constitutes a true vulnerability stems from the fact that the exact exploitation vectors are not clearly defined in the original description, making it difficult to assess the practical risk level. However, the presence of any memory leak in a core utility function represents a security concern that should be addressed through proper code review and memory management practices.
Mitigation strategies for this vulnerability should focus on upgrading to Vilistextum version 2.6.9 or later, which contains the necessary memory management fixes. Organizations should also implement monitoring systems to detect unusual memory consumption patterns that might indicate exploitation attempts. Additionally, input validation and rate limiting mechanisms can help reduce the potential impact of attacks targeting this vulnerability by limiting the frequency of requests that could trigger the problematic code path. The fix typically involves ensuring proper memory deallocation when the tmp_align variable is processed, preventing the accumulation of unreleased memory blocks that characterize this type of memory leak.