CVE-2014-0155 in Linux
Summary
by MITRE
The ioapic_deliver function in virt/kvm/ioapic.c in the Linux kernel through 3.14.1 does not properly validate the kvm_irq_delivery_to_apic return value, which allows guest OS users to cause a denial of service (host OS crash) via a crafted entry in the redirection table of an I/O APIC. NOTE: the affected code was moved to the ioapic_service function before the vulnerability was announced.
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Analysis
by VulDB Data Team • 05/10/2026
The vulnerability described in CVE-2014-0155 represents a critical denial of service flaw within the Linux kernel's virtualization subsystem, specifically affecting KVM (Kernel-based Virtual Machine) implementations. This issue resides in the ioapic_deliver function located in virt/kvm/ioapic.c, which handles I/O APIC (Advanced Programmable Interrupt Controller) redirection table management. The vulnerability arises from insufficient validation of return values from the kvm_irq_delivery_to_apic function, creating a pathway for malicious guest operating systems to exploit the host system's virtualization layer. The flaw demonstrates a classic example of improper input validation within kernel space code, where the absence of proper error checking allows arbitrary guest code execution to potentially crash the host operating system.
The technical implementation of this vulnerability stems from the kernel's handling of interrupt delivery mechanisms in virtualized environments. When a guest OS attempts to configure entries in the I/O APIC redirection table, the ioapic_deliver function processes these requests without adequately verifying the success or failure of the kvm_irq_delivery_to_apic operation. This function is responsible for routing interrupts from virtual I/O devices to the appropriate virtual CPUs within the guest environment. The improper validation means that when the kvm_irq_delivery_to_apic function returns an error condition or unexpected value, the ioapic_deliver function fails to handle this gracefully, leading to potential kernel panic or system crash. This represents a CWE-252 weakness, specifically an "Unchecked Return Value" vulnerability where the return code of a function call is not properly checked or handled.
The operational impact of this vulnerability extends beyond simple denial of service, as it can be exploited by malicious guest users to systematically crash host systems running KVM virtual machines. An attacker with access to a guest operating system could craft specific entries in the I/O APIC redirection table that trigger the unchecked return value scenario, potentially causing the host kernel to crash and resulting in complete system unavailability. This vulnerability affects Linux kernel versions through 3.14.1, representing a significant security concern for virtualization environments where multiple guest operating systems share the same physical host. The impact is particularly severe in cloud computing and virtualization infrastructure environments where a single compromised guest could potentially affect the stability and availability of the entire host system.
The mitigation strategies for CVE-2014-0155 primarily involve updating to patched kernel versions where the return value validation has been properly implemented. The fix for this vulnerability involved modifying the ioapic_deliver function to properly check and handle the return value from kvm_irq_delivery_to_apic, ensuring that error conditions are appropriately managed without causing system crashes. Organizations should implement immediate kernel updates and patches, particularly in virtualized environments where multiple guest systems are present. The vulnerability's classification under ATT&CK technique T1499.004 (Endpoint Denial of Service) highlights its potential for abuse in broader attack scenarios where attackers seek to disrupt service availability. Additionally, system administrators should consider implementing monitoring solutions to detect unusual patterns in I/O APIC table modifications, as this vulnerability can be used as part of more sophisticated attack vectors targeting virtualization infrastructure. The remediation process should also include thorough testing of updated kernel versions to ensure that the patch does not introduce compatibility issues with existing virtualization workloads.