CVE-2016-10024 in Xen
Summary
by MITRE
Xen through 4.8.x allows local x86 PV guest OS kernel administrators to cause a denial of service (host hang or crash) by modifying the instruction stream asynchronously while performing certain kernel operations.
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Analysis
by VulDB Data Team • 05/14/2026
The vulnerability identified as CVE-2016-10024 represents a critical security flaw in the Xen hypervisor affecting versions 4.8.x and earlier. This issue specifically targets para-virtualized x86 guest operating systems where local kernel administrators can exploit a fundamental race condition in the hypervisor's instruction stream handling mechanisms. The vulnerability arises from the asynchronous modification of instruction streams during kernel operations, creating a scenario where malicious guest administrators can manipulate the execution flow in ways that directly impact the host system's stability and operational integrity.
The technical flaw manifests through a race condition vulnerability that exists in how Xen handles instruction stream modifications during kernel operations. When a para-virtualized guest OS kernel administrator executes specific kernel operations, the hypervisor fails to properly synchronize access to instruction streams, allowing for asynchronous modifications that can corrupt the execution context. This flaw falls under CWE-362, which specifically addresses race conditions in concurrent systems, and more broadly relates to CWE-284, concerning improper access control mechanisms. The vulnerability exploits the hypervisor's failure to maintain proper memory isolation and execution context integrity when guest kernels perform operations that require instruction stream manipulation, creating a pathway for denial of service attacks that can either hang or crash the entire host system.
The operational impact of this vulnerability extends far beyond simple service disruption, as it represents a fundamental threat to hypervisor stability and multi-tenant cloud environments. Local administrators within para-virtualized guest systems can leverage this weakness to execute denial of service attacks that compromise the entire hosting infrastructure, potentially affecting multiple virtual machines and their associated workloads. The implications are particularly severe in cloud computing environments where multiple customers share the same physical hardware, as a single compromised guest could bring down the entire host system and affect other tenants. This vulnerability directly impacts the core principle of hypervisor security by undermining the isolation guarantees that virtualization platforms are designed to provide, creating a scenario where guest administrators can escalate their privileges to affect host-level operations.
Mitigation strategies for CVE-2016-10024 must address both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities. The primary solution involves upgrading to Xen hypervisor versions 4.9.0 and later, which contain patches specifically designed to address the race condition in instruction stream handling. Organizations should also implement strict access controls and monitoring within guest environments to detect anomalous kernel operations that might indicate exploitation attempts. The mitigation approach aligns with ATT&CK technique T1499, which covers network disruption and denial of service attacks, requiring defensive measures that include hypervisor hardening and continuous monitoring of guest kernel activities. Additionally, implementing proper kernel module signing and execution control mechanisms can help prevent unauthorized instruction stream modifications, while regular security audits of virtualization environments should include checks for similar race condition vulnerabilities in hypervisor components.