CVE-2018-12127 in Intel
Summary
by MITRE
Microarchitectural Load Port Data Sampling (MLPDS): Load ports 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 vulnerability identified as CVE-2018-12127 represents a microarchitectural side-channel attack mechanism known as Microarchitectural Load Port Data Sampling or MLPDS. This flaw resides within the speculative execution capabilities of certain intel processors and operates at the fundamental level of processor microarchitecture. The vulnerability specifically targets load ports within the processor's execution units where data is temporarily stored during speculative execution phases. Attackers can exploit this weakness to potentially extract sensitive information from the processor's internal data pathways, making it particularly concerning for systems handling confidential data. The vulnerability affects a range of intel processor models and is categorized under the broader class of side-channel attacks that leverage processor microarchitectural features to infer information about protected data.
The technical implementation of MLPDS occurs when the processor's load ports store data temporarily during speculative execution cycles. Under normal operation, these load ports hold data that may be needed for future instruction execution, but during speculative execution these storage locations can contain information about previously processed data. An authenticated local attacker with access to the system can potentially monitor these load port contents through cache timing attacks or similar side-channel techniques. The vulnerability stems from the processor's inability to properly isolate speculative execution data from the actual execution path, creating a pathway for information leakage. This type of flaw typically requires an attacker to be locally authenticated on the target system and operates under the principle that data remains accessible in processor caches even after it has been logically removed from the execution pipeline. The vulnerability aligns with CWE-203: Observable Behavioral Vulnerability and represents a sophisticated exploitation of the processor's microarchitectural design.
The operational impact of MLPDS extends beyond simple information disclosure, as it can potentially enable attackers to extract cryptographic keys, passwords, or other sensitive data from memory locations that should be protected. The attack requires local access and authentication, making it less severe than remote attacks but still highly concerning for environments where physical access is possible or where privilege escalation is achievable. Systems running affected intel processors are vulnerable to this attack, particularly those handling sensitive information or operating in environments where local attackers may exist. The vulnerability affects systems where speculative execution is enabled, which includes most modern processors from intel's core i series and other affected microarchitectures. Organizations using these processors face potential exposure to attackers who can leverage the microarchitectural weakness to extract confidential information from memory locations that are normally protected by the processor's security mechanisms.
Mitigation strategies for MLPDS involve both software and hardware approaches that address the root cause of the vulnerability at the microarchitectural level. Intel has released microcode updates to address this vulnerability, which modify the processor's behavior to prevent the leakage of information through load port data sampling. These updates typically disable or modify the speculative execution behavior that enables the attack vector. System administrators should ensure that all affected processors receive the appropriate microcode updates and that systems are properly configured to disable speculative execution where possible. Additional mitigations include implementing proper access controls to limit local authentication opportunities, monitoring for suspicious activity patterns that might indicate exploitation attempts, and considering the use of hardware security modules or other cryptographic protections to reduce the impact of potential information disclosure. The vulnerability's classification under the ATT&CK framework includes techniques related to privilege escalation and credential access through side-channel attacks. Organizations should also consider implementing comprehensive monitoring solutions that can detect unusual cache behavior or timing patterns that might indicate exploitation attempts. Regular security assessments and vulnerability scanning should include checks for proper microcode installation and verification of processor configurations to ensure that the vulnerability remains properly mitigated across all affected systems.