CVE-2006-5780 in Omni-NFS Server
Summary
by MITRE
Stack-based buffer overflow in nfsd.exe in XLink Omni-NFS Server 5.2 allows remote attackers to execute arbitrary code via a crafted TCP packet to port 2049 (nfsd), as demonstrated by vd_xlink.pm.
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Analysis
by VulDB Data Team • 04/26/2026
The vulnerability identified as CVE-2006-5780 represents a critical stack-based buffer overflow flaw in the nfsd.exe component of XLink Omni-NFS Server version 5.2. This issue specifically affects the Network File System (NFS) daemon that operates on TCP port 2049, which is the standard port for NFS services. The vulnerability arises from insufficient input validation when processing network packets, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized code execution privileges. The flaw was demonstrated through the exploitation of the vd_xlink.pm module, which serves as a verification mechanism for the vulnerability's existence and exploitability.
The technical implementation of this buffer overflow occurs when the nfsd.exe process receives a malformed TCP packet on port 2049. The stack-based nature of the vulnerability means that the overflow occurs within the program's stack memory space, where local variables and function call information are stored. When an attacker crafts a specially designed packet that exceeds the allocated buffer size, it overflows into adjacent stack memory locations, potentially corrupting the return addresses and execution flow of the program. This type of vulnerability falls under CWE-121, which specifically addresses stack-based buffer overflow conditions, and represents a classic example of how improper input validation can lead to arbitrary code execution. The attack vector requires no authentication and can be executed entirely over the network, making it particularly dangerous for systems running vulnerable NFS services.
The operational impact of this vulnerability extends beyond simple remote code execution, as it can lead to complete system compromise when exploited successfully. An attacker who successfully exploits this vulnerability gains the ability to execute arbitrary code with the privileges of the nfsd service, which typically runs with elevated permissions. This can result in unauthorized access to shared files, system enumeration, privilege escalation, and potentially complete system takeover. The vulnerability affects organizations using XLink Omni-NFS Server 5.2 in enterprise environments where NFS services are exposed to untrusted networks, creating significant risk for data integrity and system availability. From an ATT&CK framework perspective, this vulnerability maps to techniques involving remote code execution and privilege escalation, with potential for lateral movement through compromised systems. The exploitability of this vulnerability is enhanced by the fact that NFS services are commonly exposed on standard ports and often lack proper network segmentation or access controls, making them prime targets for exploitation.
Mitigation strategies for CVE-2006-5780 should focus on immediate patching of the XLink Omni-NFS Server software to the latest available version that addresses this specific buffer overflow vulnerability. Organizations should also implement network segmentation to restrict access to port 2049, ensuring that only trusted hosts can communicate with NFS services. Additional protective measures include deploying network intrusion detection systems that can identify and alert on suspicious NFS traffic patterns, implementing firewall rules to block unnecessary NFS service access, and conducting regular vulnerability assessments to identify other potentially vulnerable services. The remediation process should also include monitoring for signs of exploitation attempts and establishing incident response procedures for handling potential compromise events. Security teams should also consider disabling NFS services entirely if they are not required for business operations, as this eliminates the attack surface associated with the vulnerable service. Organizations should also ensure that proper network access controls are in place to prevent unauthorized access to NFS services and that all systems are regularly updated to address known vulnerabilities in network services.