CVE-2018-7725 in ZZIPlib
Summary
by MITRE
An issue was discovered in ZZIPlib 0.13.68. An invalid memory address dereference was discovered in zzip_disk_fread in mmapped.c. The vulnerability causes an application crash, which leads to denial of service.
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Analysis
by VulDB Data Team • 07/10/2025
The vulnerability identified as CVE-2018-7725 represents a critical memory safety issue within ZZIPlib version 0.13.68, a widely used library for handling zip archive files in various software applications. This flaw resides in the zzip_disk_fread function located within the mmapped.c source file, demonstrating how seemingly minor implementation details can lead to significant security consequences. The vulnerability manifests as an invalid memory address dereference, a classic type of memory corruption issue that occurs when a program attempts to access memory locations that have not been properly allocated or are otherwise inaccessible.
The technical nature of this vulnerability places it squarely within CWE-476, which categorizes null pointer dereference conditions that can lead to application crashes and system instability. When the zzip_disk_fread function processes certain malformed or specially crafted zip archive files, it fails to properly validate memory pointers before attempting to dereference them. This improper validation leads to a segmentation fault or access violation that terminates the executing application. The flaw specifically affects the memory mapping functionality within the library, where the application attempts to read data from memory-mapped file regions without adequate bounds checking or pointer validation mechanisms.
From an operational perspective, this vulnerability creates a reliable denial of service condition that can be exploited by attackers who possess the ability to upload or otherwise influence the input processed by applications utilizing ZZIPlib. The impact extends beyond simple application crashes to potentially disrupt entire service availability, particularly in environments where zip file processing is a core function. Systems that rely on ZZIPlib for archive handling, including web applications, file processing services, and content management systems, become vulnerable to this attack vector. The vulnerability's exploitation requires minimal privileges and can be executed through standard file upload mechanisms, making it particularly dangerous in web-facing applications.
Security practitioners should consider this vulnerability in the context of the ATT&CK framework's privilege escalation and denial of service tactics, where adversaries can leverage such flaws to disrupt service availability or gain unauthorized access to system resources. The remediation strategy focuses primarily on upgrading to patched versions of ZZIPlib, as the vulnerability cannot be effectively mitigated through code-level workarounds due to its fundamental nature within the library's memory management implementation. Organizations utilizing this library should implement comprehensive patch management procedures to ensure all affected systems receive timely updates, while also considering network-level controls to restrict access to zip file processing capabilities where possible. Additionally, input validation and sanitization measures should be implemented at application layers to provide defense-in-depth protection against malformed archive files that might trigger this vulnerability.