CVE-2004-0264 in palmhttpd
Summary
by MITRE
palmhttpd for PalmOS allows remote attackers to cause a denial of service (crash) by establishing two simultaneous HTTP connections, which exceeds the PalmOS accept queue.
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Analysis
by VulDB Data Team • 08/06/2025
The vulnerability identified as CVE-2004-0264 affects palmhttpd, a web server component used in PalmOS devices that enables HTTP protocol support for network communications. This flaw represents a classic resource exhaustion attack vector that exploits the limited connection handling capabilities of embedded operating systems. The vulnerability specifically targets the PalmOS accept queue mechanism, which serves as the primary queue for managing incoming connection requests. When two simultaneous HTTP connections are established, the palmhttpd service fails to properly manage this concurrent access pattern, leading to a system crash that results in complete denial of service for the affected device.
The technical implementation of this vulnerability stems from inadequate connection queue management within the PalmOS web server implementation. PalmOS devices typically operate with constrained resources and limited memory allocation for network services, making them particularly susceptible to queue overflow conditions. When the accept queue reaches its maximum capacity of two connections, any additional connection attempts cause the service to crash rather than gracefully handling the overflow or queuing additional requests. This behavior aligns with CWE-129, which addresses improper handling of buffer overflow conditions, and represents a fundamental design flaw in the connection management architecture. The vulnerability demonstrates poor resource management practices that are common in embedded systems where memory constraints and processing power limitations prevent robust error handling mechanisms.
The operational impact of this vulnerability extends beyond simple service disruption to encompass complete device unavailability and potential data loss. PalmOS devices that rely on web connectivity for synchronization, configuration updates, or network communications become completely non-functional until manually rebooted. This creates a significant risk for mobile professionals who depend on these devices for business operations, as the denial of service can occur remotely without physical access to the device. The vulnerability can be exploited by any remote attacker who can establish HTTP connections to the device, making it particularly dangerous in environments where PalmOS devices are used in enterprise settings or public networks. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, which covers network denial of service attacks, and demonstrates how resource exhaustion attacks can be leveraged against embedded systems with limited defensive capabilities.
Mitigation strategies for CVE-2004-0264 focus primarily on device-level protection measures and network segmentation approaches. Organizations should implement network access controls that limit HTTP connection attempts to PalmOS devices, effectively preventing the exploitation of this vulnerability. Device administrators should consider disabling unnecessary web services or implementing connection rate limiting mechanisms that prevent multiple simultaneous connections from overwhelming the accept queue. Additionally, regular firmware updates and patches should be deployed to address the underlying implementation flaw in palmhttpd. The vulnerability highlights the importance of robust resource management in embedded systems and serves as a reminder that devices with limited computational resources require careful attention to connection handling and queue management. Network monitoring should be implemented to detect unusual connection patterns that might indicate exploitation attempts, and device redundancy measures should be considered for critical applications where PalmOS device availability is essential.