CVE-2017-5980 in ZZIPlib
Summary
by MITRE
The zzip_mem_entry_new function in memdisk.c in zziplib 0.13.62 allows remote attackers to cause a denial of service (NULL pointer dereference and crash) via a crafted ZIP file.
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Analysis
by VulDB Data Team • 07/10/2025
The vulnerability identified as CVE-2017-5980 resides within the zziplib library version 0.13.62, specifically in the zzip_mem_entry_new function located in the memdisk.c file. This flaw represents a critical security issue that can be exploited by remote attackers to execute a denial of service attack against systems utilizing this library. The vulnerability manifests when the library processes a specially crafted ZIP file that triggers a NULL pointer dereference, leading to an application crash and subsequent service disruption. The zziplib library serves as a lightweight decompression library for reading zip archives, commonly used in various applications and systems that require zip file handling capabilities.
The technical nature of this vulnerability stems from inadequate input validation within the memory disk handling component of zziplib. When the zzip_mem_entry_new function encounters a malformed or crafted ZIP file, it fails to properly validate the structure of the archive before attempting to access memory locations. This lack of proper bounds checking and input sanitization results in the function attempting to dereference a NULL pointer, which causes the application to crash immediately. The flaw is categorized under CWE-476 as a NULL pointer dereference, representing a classic software vulnerability pattern where a program attempts to access memory through a null pointer reference. This type of vulnerability is particularly dangerous in library contexts where multiple applications may be affected by a single flawed component.
The operational impact of this vulnerability extends beyond simple service disruption as it can be leveraged by attackers to create persistent denial of service conditions against systems that rely on zziplib for zip file processing. Applications that utilize this library for handling user-uploaded content, automated file processing, or any scenario involving external zip archive parsing become vulnerable to this attack vector. The vulnerability can be exploited remotely through any mechanism that allows a malicious user to provide a crafted ZIP file to a system running an application linked against the vulnerable zziplib version. This includes web applications, file processing services, backup systems, and any software that handles zip archives without proper input validation. The crash occurs at the memory management level, making it particularly effective for causing system instability and service unavailability.
Mitigation strategies for this vulnerability involve immediate patching of the zziplib library to version 0.13.63 or later, which contains the necessary fixes for the NULL pointer dereference issue. System administrators should conduct thorough vulnerability assessments to identify all applications and services that depend on zziplib, ensuring comprehensive remediation across the entire infrastructure. Additionally, implementing input validation mechanisms at the application level can provide defense-in-depth measures, such as validating zip file structures before passing them to the library functions. The ATT&CK framework categorizes this type of vulnerability under T1499.004 for Network Denial of Service, highlighting the importance of proper input validation and memory management practices. Organizations should also consider implementing monitoring and alerting mechanisms to detect unusual crash patterns that might indicate exploitation attempts, while maintaining up-to-date security patches for all third-party libraries and components in their software supply chain.