CVE-2016-7929 in macOS
Summary
by MITRE
The Juniper PPPoE ATM parser in tcpdump before 4.9.0 has a buffer overflow in print-juniper.c:juniper_parse_header().
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Analysis
by VulDB Data Team • 05/16/2026
The vulnerability identified as CVE-2016-7929 represents a critical buffer overflow flaw within the tcpdump network packet analysis tool, specifically affecting versions prior to 4.9.0. This issue resides in the Juniper PPPoE ATM parser implementation, where the function juniper_parse_header() in the print-juniper.c source file fails to properly validate input data lengths before copying data into fixed-size buffers. The flaw occurs when tcpdump processes network packets containing specially crafted Juniper PPPoE ATM headers, which can trigger unauthorized memory access patterns that exceed the allocated buffer boundaries. This type of vulnerability falls under the common weakness enumeration CWE-121, which categorizes buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it presents a potential path for remote code execution within the context of the tcpdump process. When an attacker crafts malicious network traffic containing malformed Juniper PPPoE ATM headers, the buffer overflow can corrupt stack memory, potentially allowing for arbitrary code execution if the application is running with elevated privileges. The attack vector requires the victim system to be actively processing network traffic through tcpdump, making this vulnerability particularly concerning for network monitoring systems, security appliances, and network administrators who rely on tcpdump for packet analysis. This weakness aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, as successful exploitation could enable attackers to execute malicious payloads through compromised network monitoring infrastructure.
Mitigation strategies for CVE-2016-7929 primarily focus on immediate version upgrades to tcpdump 4.9.0 or later, which contain patched implementations of the juniper_parse_header() function with proper input validation and bounds checking. Network administrators should also consider implementing additional security measures such as network segmentation to limit exposure, deploying intrusion detection systems to monitor for suspicious packet patterns, and establishing regular vulnerability assessment procedures to identify other potential buffer overflow vulnerabilities in network analysis tools. The fix implemented in the patched versions typically involves introducing proper bounds checking mechanisms, using safer string manipulation functions, and ensuring that all input data is validated against maximum expected lengths before memory allocation occurs. Organizations should also review their network monitoring tool configurations to ensure that only necessary protocols are being analyzed and that appropriate access controls are in place to limit potential exploitation vectors.