Memory Exhaustion in NanaZip WebAssembly Handler

Executive Summary

CVE-2026-55782 is a vulnerability in NanaZip's WebAssembly parser that allows an attacker to cause unbounded memory allocation. This happens because the parser allocates buffers based on attacker-controlled 32-bit section and custom-name length fields without validating these lengths against the actual data size in the file.

An attacker can craft a small malicious WebAssembly (.wasm) file with manipulated section or name length fields that force the program to allocate multi-gigabyte amounts of memory during listing or extraction operations. This can lead to memory exhaustion or cause the process to terminate unexpectedly.

The vulnerability affects NanaZip versions prior to 6.5.1749.0 and has been fixed in that version.

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Impact Analysis

This vulnerability can impact you by causing a denial of service (DoS) condition on your system running vulnerable versions of NanaZip.

Specifically, an attacker can exploit this issue to exhaust system memory by forcing the application to allocate very large buffers, which can lead to application crashes or termination.

Exploitation requires minimal privileges and some user interaction, such as opening or extracting a crafted WebAssembly archive.

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Detection Guidance

This vulnerability arises when NanaZip processes a crafted WebAssembly (.wasm) file that contains attacker-controlled length fields causing excessive memory allocation and potential process termination.

Detection can involve monitoring NanaZip processes for abnormal memory usage or crashes during listing or extraction of .wasm archives.

Since the issue is triggered by specific malformed .wasm files, scanning for usage of vulnerable NanaZip versions (prior to 6.5.1749.0) and checking logs for crashes or memory exhaustion events during archive operations can help identify exploitation attempts.

No specific commands are provided in the available resources, but general approaches include:

• Use system monitoring tools (e.g., Task Manager, top, or resource monitors) to detect NanaZip processes consuming unusually large amounts of memory.
• Check application logs or Windows Event Viewer for crashes or termination events related to NanaZip.
• Identify the installed version of NanaZip using commands like `Get-Command nanazip` or checking the application properties to confirm if it is older than 6.5.1749.0.

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Mitigation Strategies

The primary mitigation step is to update NanaZip to version 6.5.1749.0 or later, where this vulnerability has been fixed.

Until the update can be applied, avoid opening or extracting untrusted or suspicious WebAssembly (.wasm) archives using NanaZip to prevent triggering the memory exhaustion.

Additionally, monitor NanaZip processes for abnormal memory usage or crashes as a precaution.

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Compliance Impact

The vulnerability in NanaZip allows for unbounded memory allocation leading to denial of service (DoS) conditions, which impacts system availability.

There is no information provided in the available resources about how this vulnerability affects compliance with common standards and regulations such as GDPR or HIPAA.

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