CVE-2016-7986 in macOS
Summary
by MITRE
The GeoNetworking parser in tcpdump before 4.9.0 has a buffer overflow in print-geonet.c, multiple functions.
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Analysis
by VulDB Data Team • 05/16/2026
The vulnerability identified as CVE-2016-7986 represents a critical buffer overflow condition within the GeoNetworking protocol parser of tcpdump software version 4.9.0 and earlier. This flaw exists specifically within the print-geonet.c source file and affects multiple functions responsible for processing GeoNetworking packets. The GeoNetworking protocol is part of the European Telecommunications Standards Institute's TS 102 636 standard, designed for wireless communication in intelligent transportation systems and other vehicular networking applications. The buffer overflow vulnerability arises when tcpdump attempts to parse malformed or specially crafted GeoNetworking packets that exceed expected data length parameters, creating opportunities for arbitrary code execution or system compromise.
This technical flaw falls under the Common Weakness Enumeration category CWE-121, which classifies buffer overflow conditions where data is written beyond the bounds of a fixed-length buffer. The vulnerability impacts tcpdump's ability to properly validate input data from network traffic, particularly when processing GeoNetworking frames that contain unexpected or malformed field values. The issue demonstrates a classic stack-based buffer overflow scenario where insufficient bounds checking allows attackers to overwrite adjacent memory locations, potentially leading to denial of service conditions or more severe exploitation outcomes. The affected functions within print-geonet.c fail to adequately validate the length of incoming GeoNetworking packet fields before attempting to copy or process this data into fixed-size buffers.
The operational impact of this vulnerability extends significantly within network monitoring and security analysis environments where tcpdump serves as a critical tool for packet capture and analysis. Security professionals and network administrators who rely on tcpdump for traffic inspection in transportation systems, industrial control networks, or general network monitoring may experience system instability or potential compromise when processing maliciously crafted GeoNetworking traffic. The vulnerability is particularly concerning in environments where automated network monitoring systems continuously process traffic without proper input validation, as a single malformed packet could cause system crashes or enable remote code execution. This represents a direct threat to network availability and integrity, especially in mission-critical applications such as smart grid monitoring, automotive communications, or emergency response systems that utilize GeoNetworking protocols.
Mitigation strategies for CVE-2016-7986 should prioritize immediate software updates to tcpdump version 4.9.0 or later, which contain patches addressing the buffer overflow conditions in the GeoNetworking parser. Network administrators should implement additional defensive measures including network segmentation to isolate systems running tcpdump from potentially malicious traffic sources, and deploy intrusion detection systems that can identify and block malformed GeoNetworking packets. The vulnerability aligns with ATT&CK technique T1059.007, which involves the execution of malicious code through command-line interfaces, and T1499.004, which covers network disruption through denial of service attacks. Organizations should also consider implementing network traffic filtering rules that restrict the types of packets processed by tcpdump, particularly in environments where the software operates in high-risk network segments. Regular security assessments and vulnerability scanning should include verification of tcpdump installations to ensure proper patch levels and prevent exploitation of this buffer overflow vulnerability.