CVE-2025-61146 in libsixel
Summary
by MITRE • 02/23/2026
saitoha libsixel until v1.8.7 was discovered to contain a memory leak via the component malloc_stub.c.
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Analysis
by VulDB Data Team • 02/27/2026
The vulnerability identified as CVE-2025-61146 affects saitoha libsixel library versions prior to v1.8.7, specifically within the malloc_stub.c component. This memory leak represents a critical security weakness that can lead to resource exhaustion and potential system instability. The libsixel library is commonly used for terminal graphics rendering and image conversion, making it a widely deployed component in various applications and systems that handle graphical content in terminal environments.
The technical flaw manifests in the malloc_stub.c file where memory allocation and deallocation functions are implemented or stubbed. This component likely contains improper memory management practices that fail to correctly release allocated memory blocks, resulting in gradual memory consumption over time. The vulnerability stems from inadequate handling of memory allocation requests and subsequent deallocation, creating a scenario where allocated memory remains in use even after it should be freed. This type of memory leak can occur through various mechanisms including failure to call free() on allocated memory, incorrect pointer management, or improper handling of allocation failures.
The operational impact of this memory leak vulnerability can be severe in environments where the affected library is extensively used. Systems utilizing libsixel for terminal graphics may experience progressive memory consumption that eventually leads to performance degradation, application crashes, or complete system resource exhaustion. In server environments or long-running applications, this memory leak can cause systems to become unresponsive or require frequent restarts to maintain operational stability. The vulnerability is particularly concerning in resource-constrained environments where memory management is critical for system performance and reliability.
Security implications extend beyond simple performance degradation as memory leaks can potentially enable denial of service attacks or create conditions where attackers might exploit the resource exhaustion for further malicious activities. The vulnerability aligns with CWE-401, which specifically addresses improper handling of memory allocation failures and resource leaks in software systems. Organizations relying on affected versions of libsixel should implement immediate mitigation strategies including updating to the patched v1.8.7 release or applying custom patches to address the memory management issues in malloc_stub.c. Additionally, monitoring systems for unusual memory consumption patterns can help detect exploitation attempts and provide early warning of potential abuse of this vulnerability in production environments.