CVE-2018-7726 in ZZIPlib
Summary
by MITRE
An issue was discovered in ZZIPlib 0.13.68. There is a bus error caused by the __zzip_parse_root_directory function of zip.c. Attackers could leverage this vulnerability to cause a denial of service via a crafted zip file.
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Analysis
by VulDB Data Team • 07/10/2025
The vulnerability identified as CVE-2018-7726 represents a critical bus error within ZZIPlib version 0.13.68 that stems from improper handling of malformed zip archives. This flaw exists within the __zzip_parse_root_directory function located in the zip.c source file, where insufficient input validation leads to memory access violations during archive parsing operations. The vulnerability manifests as a bus error condition that occurs when the library attempts to process specially crafted zip files that contain malformed directory structures or corrupted metadata. This type of error typically arises from attempting to access memory locations that are either unmapped or inaccessible due to improper bounds checking or pointer arithmetic. The issue affects systems that utilize ZZIPlib for zip file processing, particularly those implementing the library in applications that handle untrusted archive data without proper sanitization measures.
The technical exploitation of this vulnerability requires crafting a malicious zip file that triggers the specific parsing path within the __zzip_parse_root_directory function. When ZZIPlib encounters such malformed input, the function fails to properly validate the archive structure, leading to a bus error that typically results in program termination or system crash. This behavior aligns with CWE-125, which describes out-of-bounds read vulnerabilities, and CWE-787, which covers out-of-bounds write conditions. The vulnerability can be classified under the ATT&CK technique T1203, where adversaries may leverage software weaknesses to cause system instability or denial of service conditions. The bus error occurs at the kernel or system level, making it particularly dangerous as it can potentially crash the entire system or cause applications using the library to terminate unexpectedly, thereby creating a denial of service scenario.
The operational impact of CVE-2018-7726 extends beyond simple service disruption as it can affect a wide range of applications that depend on ZZIPlib for zip archive handling. Systems utilizing this library include various file management tools, backup applications, and web services that process user-uploaded zip files without proper validation. When exploited, the vulnerability can cause cascading failures in applications that rely on the library, potentially leading to complete system unavailability or data processing interruptions. The vulnerability is particularly concerning in environments where automated processing of zip files occurs, such as content delivery networks, file sharing platforms, or backup systems that automatically extract archive contents. Organizations running affected software may experience unexpected application crashes, service interruptions, and potential data loss if the system fails to recover properly from the bus error condition. The impact is further amplified when considering that many applications may not implement proper error handling for such low-level system failures, leading to complete service degradation.
Mitigation strategies for CVE-2018-7726 should prioritize immediate patching of ZZIPlib to version 0.13.69 or later, which contains the necessary fixes for the directory parsing vulnerability. Organizations should also implement input validation measures that sanitize zip file contents before processing, including verifying archive integrity and checking for malformed structures. Network-level defenses can include implementing content filtering that scans zip files for known malicious patterns or suspicious metadata structures. System administrators should monitor for unusual application crashes or service interruptions that may indicate exploitation attempts. The fix addresses the root cause by implementing proper bounds checking and input validation within the __zzip_parse_root_directory function, preventing the bus error condition from occurring. Additionally, organizations should consider implementing application sandboxing or containerization techniques to limit the potential impact of successful exploitation attempts. Regular security assessments of third-party libraries and dependencies should be conducted to identify similar vulnerabilities in other components of the software stack, as this vulnerability demonstrates the importance of proper memory management and input validation in archive processing libraries.