CVE-2026-92871 in Pgpool-II
Summary
by MITRE • 09/30/2026
A NULL pointer dereference vulnerability exists in Pgpool-II, which may allow an unauthenticated attacker to cause abnormal termination of the watchdog process.
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Analysis
by VulDB Data Team • 09/30/2026
The identified vulnerability represents a critical stability issue within the Pgpool-II software suite, specifically affecting its high-availability and load-balancing component known as Watchdog. This module is responsible for managing failover scenarios and maintaining cluster consistency by monitoring node health through heartbeat messages. The core technical flaw lies in improper input validation during the processing of incoming network packets or internal state transitions. When a specific sequence of events occurs, likely involving malformed data or an unexpected state change, the application attempts to access memory at address zero rather than validating that the pointer is valid before use. This NULL pointer dereference causes the operating system to send a segmentation fault signal to the process, resulting in immediate and abnormal termination of the Watchdog daemon.
From an operational perspective, this vulnerability poses a significant risk to service availability. Since Pgpool-II acts as a central point for managing database connections and failover logic, its abrupt crash can disrupt active sessions and prevent automatic recovery mechanisms from functioning correctly. An unauthenticated attacker who has network access to the port where Watchdog listens can exploit this flaw by sending crafted packets that trigger the null reference condition. This constitutes a denial of service attack vector, allowing an adversary to take down the database proxy layer without needing valid credentials or prior authentication. The impact extends beyond simple downtime; in clustered environments, the loss of the Watchdog process may lead to split-brain scenarios where multiple nodes believe they are primary, potentially causing data corruption if write operations proceed on both sides simultaneously.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-476, which describes a NULL pointer dereference error. Such errors typically arise from insufficient checks of return values or pointers before their use in subsequent function calls or memory accesses. In the context of network-facing services like Pgpool-II Watchdog, this flaw highlights gaps in robust input sanitization and state machine validation. The attack vector is classified under MITRE ATT&CK technique T1499, specifically Endpoint Denial of Service via resource exhaustion or crash induction. By exploiting this weakness, an attacker can degrade the reliability of the entire database infrastructure that relies on Pgpool-II for connection pooling and high availability management.
Mitigation strategies should focus primarily on applying vendor-provided patches as soon as they become available to address the underlying code defect. Until a patch is applied, network-level controls such as firewall rules or access control lists can be implemented to restrict connectivity to the Watchdog port exclusively from trusted internal nodes that are part of the database cluster. This limits the attack surface by preventing unauthenticated external actors from reaching the vulnerable service component. Additionally, deploying intrusion detection systems with signatures capable of identifying malformed packet patterns associated with this specific crash condition may provide an additional layer of defense against exploitation attempts in production environments where immediate patching is not feasible.