CVE-2018-12126 in Intel
Summary
by MITRE
Microarchitectural Store Buffer Data Sampling (MSBDS): Store buffers on some microprocessors utilizing speculative execution may allow an authenticated user to potentially enable information disclosure via a side channel with local access. A list of impacted products can be found here: https://www.intel.com/content/dam/www/public/us/en/documents/corporate-information/SA00233-microcode-update-guidance_05132019.pdf
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Analysis
by VulDB Data Team • 05/30/2026
The CVE-2018-12126 vulnerability represents a sophisticated microarchitectural side-channel attack targeting store buffer mechanisms in modern processors. This vulnerability falls under the broader category of microarchitectural data sampling flaws that exploit the inherent speculative execution capabilities of contemporary microprocessors. The issue specifically affects store buffers which are critical components in processor microarchitecture responsible for managing memory store operations during speculative execution phases. These buffers temporarily hold store data before it is committed to the actual memory hierarchy, creating potential leakage points for sensitive information through timing-based side-channel attacks.
The technical flaw in MSBDS stems from how store buffers handle data during speculative execution cycles, where the processor speculatively executes instructions before confirming whether the execution path is valid. When a processor performs speculative store operations, data may remain in the store buffer even after the speculative execution is abandoned, creating opportunities for information leakage. The vulnerability enables an authenticated local user to potentially extract sensitive information from the store buffer contents by observing timing variations and cache behavior patterns. This type of attack leverages the inherent timing differences in memory access operations to infer the presence and contents of data within the processor's internal buffers.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially expose cryptographic keys, passwords, and other sensitive data that resides in processor memory buffers during speculative execution. Attackers with local access to affected systems can exploit this weakness to perform cache timing attacks that reveal information about the processor's internal state. The vulnerability is particularly concerning because it operates at the microarchitectural level, making it difficult to detect through traditional software-based security measures. Systems utilizing affected processors may experience unauthorized data exposure during normal operations, especially when processing sensitive cryptographic operations or handling confidential information.
Mitigation strategies for CVE-2018-12126 typically involve microcode updates from processor manufacturers, which modify the processor's behavior to prevent the information leakage through store buffer mechanisms. These updates often include changes to the store buffer management protocols and may involve disabling or modifying speculative execution behaviors for certain operations. Organizations should implement these microcode updates promptly and verify their effectiveness through proper testing procedures. Additional mitigations include operating system-level protections and application-level defenses that can help reduce the attack surface. The vulnerability aligns with CWE-203: Information Exposure Through Implementation Artifact and relates to ATT&CK technique T1059.001: Command and Scripting Interpreter for potential exploitation scenarios involving local privilege escalation and information gathering operations.