CVE-2018-16548 in ZZIPlib
Summary
by MITRE
An issue was discovered in ZZIPlib through 0.13.69. There is a memory leak triggered in the function __zzip_parse_root_directory in zip.c, which will lead to a denial of service attack.
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Analysis
by VulDB Data Team • 08/29/2025
The vulnerability identified as CVE-2018-16548 represents a critical memory management flaw within ZZIPlib version 0.13.69 and earlier. This library serves as a comprehensive zip file handling component that processes compressed archives across multiple platforms and applications. The memory leak occurs specifically within the __zzip_parse_root_directory function located in the zip.c source file, making it a fundamental component of the zip archive parsing infrastructure. The flaw demonstrates a classic pattern of resource exhaustion where allocated memory is not properly released during the parsing process, creating a persistent memory consumption issue that can be exploited by malicious actors.
The technical implementation of this vulnerability stems from improper memory deallocation within the zip directory parsing routine. When ZZIPlib processes zip archives, the __zzip_parse_root_directory function attempts to parse the central directory structure of zip files but fails to correctly release previously allocated memory blocks. This memory leak manifests as a gradual accumulation of unused memory segments that remain allocated even after the parsing operation completes. The vulnerability is particularly concerning because it can be triggered through normal zip file processing operations, meaning that any application utilizing ZZIPlib for zip file handling becomes susceptible to this memory exhaustion attack. The flaw operates at the core of the library's archive parsing mechanism, making it a fundamental weakness that affects all applications relying on this component for zip file operations.
The operational impact of this vulnerability extends beyond simple resource consumption, presenting a significant denial of service threat to systems utilizing ZZIPlib. Attackers can exploit this weakness by crafting malicious zip files or by repeatedly processing standard zip archives, causing progressive memory consumption that eventually leads to system instability or complete service unavailability. The memory leak accumulates over time, potentially causing applications to crash or become unresponsive, particularly in environments where zip file processing occurs frequently or in high-volume scenarios. This vulnerability affects systems ranging from desktop applications to server environments where zip file handling is a routine operation, creating widespread potential for exploitation across various deployment contexts. The vulnerability's impact is amplified by the fact that it can be triggered without requiring special privileges or complex attack vectors, making it accessible to a broad range of threat actors.
Mitigation strategies for CVE-2018-16548 primarily focus on immediate library updates to versions that address the memory leak issue. Organizations should prioritize upgrading to ZZIPlib version 0.13.70 or later, where the memory management flaw has been resolved through proper memory deallocation implementation. Additionally, implementing input validation and sanitization measures can help reduce the risk of exploitation by limiting the types of zip files processed and monitoring for abnormal memory usage patterns. System administrators should also consider deploying monitoring solutions that can detect unusual memory consumption patterns indicative of the memory leak, enabling early detection and response to potential exploitation attempts. From a cybersecurity perspective, this vulnerability aligns with CWE-401, which specifically addresses improper release of memory, and represents a common attack vector categorized under the ATT&CK technique T1499.002 for network denial of service attacks. The remediation process should include thorough testing of updated libraries to ensure compatibility with existing applications while maintaining the integrity of zip file processing functionality.