CVE-2025-6498 in tidy-html5
Summary
by MITRE • 06/23/2025
A vulnerability classified as problematic has been found in HTACG tidy-html5 5.8.0. Affected is the function defaultAlloc of the file src/alloc.c. The manipulation leads to memory leak. It is possible to launch the attack on the local host. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 10/01/2025
CVE-2025-6498 represents a memory leak vulnerability within HTACG tidy-html5 version 5.8.0, specifically within the defaultAlloc function located in src/alloc.c. This flaw constitutes a CWE-401 weakness, which categorizes memory leaks as a critical concern in software security. The vulnerability manifests when the application fails to properly release allocated memory resources, creating a persistent memory consumption issue that can degrade system performance over time. The memory leak occurs during the allocation process, where the defaultAlloc function does not adequately manage memory lifecycle, leading to resource exhaustion. This vulnerability is particularly concerning as it affects the core memory management functionality of the HTML parser library, which is widely used for cleaning and validating HTML content across numerous applications and systems.
The technical exploitation of this vulnerability is confined to local host environments, meaning attackers must have local system access to trigger the memory leak condition. This limitation reduces the attack surface compared to remote exploitation vectors but still presents significant operational risks in environments where local privilege escalation is possible. The memory leak affects the application's ability to maintain optimal performance, potentially leading to system instability, reduced responsiveness, or complete application failure when memory resources become exhausted. The disclosed exploit demonstrates that attackers can repeatedly invoke the defaultAlloc function in a manner that accumulates memory consumption without proper deallocation, creating a persistent resource drain that may be difficult to detect through normal monitoring procedures.
The operational impact of CVE-2025-6498 extends beyond simple performance degradation to potentially enable more sophisticated attack vectors. Memory leaks can create conditions that facilitate other vulnerabilities such as buffer overflows or denial of service attacks, particularly when combined with other weaknesses in the system. From an ATT&CK framework perspective, this vulnerability aligns with T1499.004 - Endpoint Denial of Service, as the memory leak can be leveraged to consume system resources and potentially cause service disruption. Additionally, the vulnerability may support lateral movement techniques through resource exhaustion attacks that could affect system availability. Organizations relying on tidy-html5 for HTML processing, content management systems, web applications, and automated content validation tools are particularly at risk, as the memory leak could accumulate over time and eventually compromise system stability.
Mitigation strategies for CVE-2025-6498 should focus on immediate remediation through software updates to versions that address the memory leak in defaultAlloc function. System administrators should implement monitoring solutions that track memory consumption patterns and alert on unusual resource usage that may indicate memory leak exploitation. The implementation of proper memory management practices including regular memory profiling, leak detection tools, and code reviews can help identify similar issues in other components. Additionally, organizations should consider implementing sandboxing or containerization techniques to limit the impact of memory leaks on system stability. From a defensive perspective, network segmentation and access controls should be enforced to limit local system access and reduce the likelihood of exploitation, while regular security assessments should be conducted to identify and remediate similar memory management issues within the application stack.