CVE-2019-20797 in prboom-plus
Summary
by MITRE
An issue was discovered in e6y prboom-plus 2.5.1.5. There is a buffer overflow in client and server code responsible for handling received UDP packets, as demonstrated by I_SendPacket or I_SendPacketTo in i_network.c.
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Analysis
by VulDB Data Team • 08/29/2025
The vulnerability identified as CVE-2019-20797 represents a critical buffer overflow flaw within the prboom-plus 2.5.1.5 network implementation, specifically affecting both client and server components that process UDP packet reception. This issue resides in the i_network.c source file where the I_SendPacket and I_SendPacketTo functions handle network communication, creating a pathway for malicious actors to exploit memory corruption vulnerabilities. The flaw manifests when the software receives UDP packets that exceed predetermined buffer limits, allowing attackers to overwrite adjacent memory regions and potentially execute arbitrary code within the context of the affected application.
The technical implementation of this vulnerability stems from inadequate bounds checking in the network packet handling routines, which fail to validate the size of incoming UDP packets before copying data into fixed-size buffers. This classic buffer overflow condition occurs when the software assumes that incoming network data will not exceed expected parameters, creating a scenario where maliciously crafted packets can cause stack corruption or heap overflow conditions. The vulnerability affects both client and server implementations, meaning that any system running prboom-plus 2.5.1.5 could be compromised through network-based attacks, potentially allowing remote code execution or denial of service conditions that could disrupt gameplay or system availability.
The operational impact of this vulnerability extends beyond simple exploitation capabilities to encompass broader security implications for networked gaming environments and multiplayer applications. Attackers could leverage this flaw to execute arbitrary code on systems running vulnerable versions of prboom-plus, potentially gaining full control over affected machines or disrupting network services. The vulnerability's presence in both client and server code creates a particularly dangerous scenario where a single malicious packet could compromise multiple systems within a networked gaming environment. This type of vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a significant risk for gaming applications that rely on network communication protocols.
Mitigation strategies for CVE-2019-20797 should prioritize immediate software updates to versions that address the buffer overflow conditions in the network handling code. System administrators should implement network segmentation and firewall rules to limit UDP packet transmission to essential ports only, reducing the attack surface for potential exploitation. The implementation of input validation measures and bounds checking in network packet handling routines should be enforced throughout the application codebase to prevent similar vulnerabilities from manifesting in future versions. Additionally, monitoring network traffic for unusual UDP packet patterns and implementing intrusion detection systems can help identify potential exploitation attempts before they succeed. Organizations should also consider applying network-based security controls such as rate limiting and packet filtering to prevent exploitation attempts that rely on sending malformed packets to trigger the buffer overflow conditions. This vulnerability demonstrates the critical importance of proper memory management and input validation in networked applications, particularly in gaming environments where multiple systems interact over shared networks and where the potential for exploitation exists in both client and server implementations.