CVE-2008-4309 in net-snmp
Summary
by MITRE
Integer overflow in the netsnmp_create_subtree_cache function in agent/snmp_agent.c in net-snmp 5.4 before 5.4.2.1, 5.3 before 5.3.2.3, and 5.2 before 5.2.5.1 allows remote attackers to cause a denial of service (crash) via a crafted SNMP GETBULK request, which triggers a heap-based buffer overflow, related to the number of responses or repeats.
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Analysis
by VulDB Data Team • 05/28/2026
The vulnerability identified as CVE-2008-4309 represents a critical integer overflow flaw within the net-snmp software implementation that affects multiple versions including 5.4 before 5.4.2.1, 5.3 before 5.3.2.3, and 5.2 before 5.2.5.1. This issue resides in the netsnmp_create_subtree_cache function located in the agent/snmp_agent.c file, which forms a core component of the SNMP agent functionality. The vulnerability manifests when processing SNMP GETBULK requests, which are used by management stations to retrieve multiple variable bindings from an SNMP agent in a single request. The integer overflow occurs during the calculation of memory allocation for response handling, specifically when determining the number of responses or repeats that should be processed, creating a scenario where the calculated value exceeds the maximum representable integer, leading to unexpected behavior.
The technical exploitation of this vulnerability involves crafting a malicious SNMP GETBULK request that forces the net-snmp agent to perform an integer overflow operation during memory allocation calculations. When the vulnerable code attempts to create a subtree cache for the response data, the integer overflow causes the system to allocate insufficient memory or potentially negative memory values, resulting in a heap-based buffer overflow condition. This memory corruption directly impacts the process heap management and can lead to arbitrary code execution or process termination, ultimately causing a denial of service condition that crashes the SNMP agent daemon. The flaw demonstrates characteristics consistent with CWE-190, which specifically addresses integer overflow conditions that can lead to buffer overflows and memory corruption issues.
From an operational perspective, this vulnerability poses significant risk to network infrastructure management systems that rely on net-snmp for monitoring and management operations. The remote exploitation capability means that attackers can target SNMP agents without requiring local access or authentication credentials, making it particularly dangerous in network environments where SNMP is exposed to untrusted networks. The denial of service impact severely compromises network monitoring capabilities, potentially leaving critical infrastructure without visibility into system performance, security events, or operational status. Network administrators who depend on SNMP-based monitoring tools for alerting, performance tracking, and security incident response may experience complete loss of monitoring functionality until the vulnerable software is patched or the service is manually restarted.
The mitigation strategy for CVE-2008-4309 involves immediate deployment of patched versions of net-snmp software, specifically versions 5.4.2.1, 5.3.2.3, and 5.2.5.1 or later, which contain the necessary fixes for the integer overflow condition. System administrators should also implement network segmentation and access controls to limit SNMP traffic to trusted management stations only, reducing the attack surface for this vulnerability. Monitoring for anomalous SNMP traffic patterns and implementing intrusion detection systems that can identify crafted GETBULK requests may help detect exploitation attempts. Additionally, organizations should conduct thorough vulnerability assessments to identify all systems running vulnerable net-snmp versions and ensure that patch management procedures are in place to maintain up-to-date software versions. The ATT&CK framework categorizes this vulnerability under the T1071.004 technique for application layer protocol usage, specifically targeting SNMP protocols for network reconnaissance and service disruption activities, making it a significant concern for cybersecurity teams implementing defensive measures against protocol-based attacks.