CVE-2026-88385 in Mini-XML
Summary
by MITRE • 09/24/2026
Mini-XML 4.0.5 contains a memory leak vulnerability in mxml_load_data() during malformed XML parsing. Specially crafted XML input can cause text nodes allocated by mxmlNewText() to become unlinked before a parse error transfers control to the cleanup path. These orphaned nodes are not released, resulting in a persistent memory leak on each parsing attempt. Repeated attacker-controlled requests can cause cumulative memory exhaustion and denial of service.
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Analysis
by VulDB Data Team • 09/24/2026
The vulnerability identified in Mini-XML version 4.0.5 represents a critical resource management flaw within the library's XML parsing engine, specifically located in the mxml_load_data function. This issue arises from an improper handling of dynamic memory allocation during the processing of malformed or specially crafted XML input files. When the parser encounters specific structural anomalies that trigger a parse error, it initiates a cleanup sequence intended to free allocated resources and restore internal state consistency. However, due to a logical defect in this control flow path, certain text nodes created via mxmlNewText are effectively orphaned before they can be properly deallocated. These nodes become unlinked from the main document tree structure but remain referenced by local variables or intermediate data structures that are not correctly cleared during the error recovery process. Consequently, the memory associated with these orphaned nodes is never returned to the system heap, leading to a persistent and cumulative memory leak every time such malformed input is processed.
From an operational perspective, this vulnerability poses a significant risk of Denial of Service (DoS) for applications relying on Mini-XML for parsing untrusted or user-supplied XML data. Because the memory leak occurs repeatedly with each malicious request, an attacker can exploit this behavior to exhaust the available system memory over time. This gradual consumption of resources degrades application performance and eventually leads to process termination or system instability when the host machine runs out of virtual address space or physical RAM. The impact is particularly severe in high-throughput environments where XML parsing occurs frequently, such as web services, configuration management systems, or data ingestion pipelines that accept external input without rigorous pre-validation.
This flaw aligns with Common Weakness Enumeration (CWE) category CWE-401, which describes a missing release of memory after effective usage. The underlying technical cause is rooted in flawed error handling logic where the cleanup routine fails to traverse and free all dynamically allocated nodes that were created during the parsing session prior to the detection of the syntax error. In terms of offensive security frameworks, this vulnerability can be leveraged within ATT&CK technique T1496, Resource Hijacking, specifically under the sub-technique for Denial of Service via resource exhaustion. Attackers do not need arbitrary code execution capabilities to exploit this; they only require the ability to submit malformed XML payloads to a service that utilizes Mini-XML 4.0.5 or earlier versions with similar parsing logic.
Mitigation strategies should focus on immediate patching and defensive coding practices. The primary remediation is to upgrade to a patched version of Mini-XML where the mxml_load_data function has been corrected to ensure all allocated text nodes are properly freed during error paths. For organizations unable to immediately update their dependencies, implementing strict input validation at the application boundary can reduce exposure by rejecting malformed XML structures before they reach the parser. Additionally, deploying resource monitoring and limits such as memory quotas or container-based isolation can mitigate the impact of successful exploitation by containing the effects of memory exhaustion within defined boundaries. Developers should also review other areas of their codebase that utilize Mini-XML to ensure consistent error handling patterns are applied across all parsing operations to prevent similar leaks in different contexts.