Memory Allocation Vulnerability in MDEx Product by Leandrocp

CVE-2026-53428

What is CVE-2026-53428?

A memory allocation issue in the MDEx product allows an unauthenticated attacker to exploit unbounded memory allocation, potentially leading to denial of service. The vulnerability arises when a user-controlled inclusive line range is processed in an unbounded manner, causing significant memory consumption that can crash the application. Attackers can exploit this by embedding a specially crafted Markdown code block which, through the rendering process, allocates excessive memory resources. This results in overwhelming the host system, effectively denying service to all users relying on the rendering functionality. The affected versions include MDEx prior to 0.12.3 and mdex_native prior to 0.2.3, making timely patching critical.

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