CVE-2014-2039 in Linux
Summary
by MITRE
arch/s390/kernel/head64.S in the Linux kernel before 3.13.5 on the s390 platform does not properly handle attempted use of the linkage stack, which allows local users to cause a denial of service (system crash) by executing a crafted instruction.
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Analysis
by VulDB Data Team • 04/12/2025
The vulnerability identified as CVE-2014-2039 resides within the Linux kernel's s390 architecture implementation, specifically in the arch/s390/kernel/head64.S file. This flaw affects systems running Linux kernel versions prior to 3.13.5 on s390 platforms, which are IBM's 64-bit mainframe architectures. The vulnerability manifests when the kernel fails to properly manage attempted usage of the linkage stack, a critical component used for function call management and stack operations in the s390 architecture. The linkage stack serves as a specialized data structure that maintains the call history and return addresses for function invocations within the kernel space, making its proper handling essential for system stability.
The technical exploitation of this vulnerability occurs through the execution of crafted instructions that specifically target the linkage stack handling mechanisms. When a local user executes such malicious instructions, the kernel's improper handling of these linkage stack operations results in a system crash or complete denial of service condition. This represents a classic case of improper input validation and resource management, where the kernel fails to properly validate or handle edge cases in stack manipulation operations. 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, potentially leading to unauthorized system disruption.
From an operational impact perspective, this vulnerability poses significant risks to mainframe environments that rely on Linux kernel stability and continuous operation. The s390 platform is commonly used in enterprise environments where system uptime and reliability are critical, making denial of service attacks particularly damaging. The vulnerability allows for a straightforward denial of service attack that can bring entire systems down, potentially affecting critical business operations and requiring system administrators to perform emergency restarts or maintenance procedures. The local nature of the exploit means that any user with access to the system can potentially trigger this condition, making it a particularly concerning vulnerability in multi-user environments.
The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and more specifically relates to improper handling of stack operations within kernel space. From an ATT&CK framework perspective, this vulnerability could be categorized under T1499.004 for network denial of service and potentially T1068 for local privilege escalation if the system allows unprivileged users to execute code. The proper mitigation strategy involves upgrading to Linux kernel version 3.13.5 or later, where the linkage stack handling has been properly implemented to prevent the exploitation scenario. Additionally, system administrators should implement monitoring for unusual system behavior that might indicate attempted exploitation and ensure that all mainframe systems are kept up to date with security patches. The vulnerability demonstrates the critical importance of proper kernel stack management and the potential for seemingly minor implementation flaws to result in catastrophic system failures.