CVE-2024-36348 in EPYC 7002 Processors
Summary
by MITRE • 07/08/2025
A transient execution vulnerability in some AMD processors may allow a user process to infer the control registers speculatively even if UMIP feature is enabled, potentially resulting in information leakage.
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Analysis
by VulDB Data Team • 02/20/2026
This vulnerability represents a sophisticated transient execution flaw affecting specific AMD processor models that undermines the fundamental security protections designed to prevent unauthorized access to control registers. The issue stems from the processor's speculative execution mechanisms which, under certain conditions, can inadvertently expose information about control register contents even when the User Mode Instruction Prevention (UMIP) feature is properly enabled. The vulnerability exploits the inherent complexity of modern processor microarchitectures where speculative execution continues beyond the intended execution boundaries, creating side-channel attack vectors that bypass traditional privilege separation mechanisms.
The technical implementation of this flaw occurs at the microarchitectural level where AMD processors execute instructions speculatively before the actual execution path is determined. When a user process attempts to access control registers, the processor's speculative execution engine may temporarily load and process these register values in the execution pipeline even though the access would normally be blocked by UMIP. This creates a window where information leakage can occur through cache timing attacks or other side-channel techniques that monitor the processor's behavior during speculative execution phases. The vulnerability specifically affects processors that implement certain microarchitectural features while maintaining compatibility with older instruction sets, creating a unique attack surface that has not been previously exploited at scale.
The operational impact of this vulnerability extends beyond simple information disclosure as it represents a fundamental breakdown in processor-level security boundaries that could enable more sophisticated attacks. An attacker with user-level privileges could potentially extract sensitive information about system state, including register contents that should normally be protected from user processes. This capability could be leveraged to reconstruct information about other processes running on the same system, potentially compromising the integrity of multi-tenant environments or exposing sensitive data in virtualized deployments. The transient nature of the vulnerability means that traditional software-based mitigations may be insufficient, as the information leakage occurs during the speculative execution phase rather than during actual instruction execution, making it particularly challenging to detect and prevent through conventional security mechanisms.
Mitigation strategies for this vulnerability typically involve a combination of microcode updates from AMD, kernel-level patches, and potential architectural modifications to processor behavior during speculative execution. System administrators should prioritize updating processor microcode to versions that address the specific transient execution pathways exploited by this vulnerability, while also implementing kernel mitigations such as enhanced memory management and control register access monitoring. The solution approach aligns with the principles outlined in the CWE-1167 category for transient execution vulnerabilities and follows recommendations from the MITRE ATT&CK framework for privilege escalation techniques. Organizations should also consider implementing additional monitoring and detection mechanisms that can identify anomalous processor behavior patterns indicative of speculative execution attacks, as these vulnerabilities often require sophisticated detection approaches that go beyond traditional security monitoring tools and require deep understanding of processor microarchitectural behavior.