CVE-2006-3635 in Linux
Summary
by MITRE
The ia64 subsystem in the Linux kernel before 2.6.26 allows local users to cause a denial of service (stack consumption and system crash) via a crafted application that leverages the mishandling of invalid Register Stack Engine (RSE) state.
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Analysis
by VulDB Data Team • 03/04/2025
The vulnerability described in CVE-2006-3635 represents a critical flaw in the ia64 architecture subsystem of the Linux kernel affecting versions prior to 2.6.26. This issue specifically targets the Register Stack Engine (RSE) handling mechanisms that are fundamental to the Itanium architecture's operation. The RSE is a hardware feature designed to manage register state during function calls and context switches, making it a crucial component for system stability and performance. When a local user crafts a specific application that exploits the improper handling of invalid RSE states, the kernel becomes vulnerable to a denial of service condition that can result in complete system crashes.
The technical flaw manifests through the kernel's inadequate validation and processing of malformed RSE state information during system calls or context switches. In the ia64 architecture, the Register Stack Engine maintains a stack of register states that must be properly managed during program execution. When an application deliberately manipulates or corrupts the RSE state in specific ways, the kernel's ia64 subsystem fails to properly handle these invalid conditions. This failure leads to uncontrolled stack consumption where the kernel's memory management structures become corrupted, ultimately resulting in system instability and potential crashes. The vulnerability operates at the kernel level, making it particularly dangerous as it can be exploited by any local user with access to the system, regardless of their privileges.
The operational impact of this vulnerability extends beyond simple denial of service, as it can lead to complete system compromise and data loss. System administrators face the risk of unexpected system crashes, which can result in service interruptions, data corruption, and potential security breaches if the system is not properly monitored. The vulnerability affects systems running Linux on Itanium hardware platforms, which were commonly used in high-performance computing environments and enterprise servers. Organizations relying on these systems for critical operations must consider the potential for unexplained system downtime and the associated business impact. The local nature of the exploit means that even unprivileged users can potentially disrupt system operations, making this vulnerability particularly concerning for multi-user environments.
Mitigation strategies for this vulnerability require immediate kernel updates to version 2.6.26 or later, which contain the necessary patches to properly handle invalid RSE states. System administrators should prioritize patch deployment across all affected systems, particularly those running Itanium-based hardware. Additional protective measures include implementing proper system monitoring to detect unusual stack consumption patterns and establishing robust incident response procedures for handling system crashes. The vulnerability aligns with CWE-129, which addresses improper handling of invalid input, and can be categorized under ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also consider implementing kernel hardening measures and restricting local user privileges where possible to minimize potential exploitation risks. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar issues in other kernel subsystems.