VulnerabilityPublished 4 Jan 2018Updated 21 Nov 2025

Red Hat Security Advisory: microcode_ctl security update

Affects Red Hat microcode_ctlSource GCVE Database

Mentioned vulnerabilities

CVE-2017-5715

Severity

High

Rated by Threat Radar

Data as of 13 Nov 2026, 18:31 UTC

What to do

AI-suggested

Red Hat has released microcode_ctl package updates to mitigate this vulnerability. Users should apply these microcode updates as part of their system patching process. Since this is a microcode-level fix, applying the update is necessary to fully mitigate the issue alongside kernel-level patches.

Description

The microcode_ctl packages for Intel and AMD processors received a security update addressing an industry-wide speculative execution vulnerability known as CVE-2017-5715. This flaw allows an unprivileged attacker to exploit branch target injection to read privileged memory via cache side-channel attacks crossing syscall and guest/host boundaries. The update corresponds to the microcode counterpart of the kernel mitigation for this issue.

Impact

An unprivileged attacker could exploit this vulnerability to read privileged memory across syscall and guest/host boundaries by leveraging targeted cache side-channel attacks. This could lead to unauthorized disclosure of sensitive information from privileged contexts.

Summary

This advisory addresses CVE-2017-5715, a speculative execution vulnerability affecting many modern microprocessor designs. The flaw involves branch target injection, where an attacker can trigger speculative execution of instructions that access privileged memory. Although these instructions do not retire, they can cause data to be loaded into the processor's cache, which can then be probed by an attacker to infer privileged information. The microcode_ctl package provides microcode updates to mitigate this hardware-level vulnerability. This update complements kernel-level mitigations and is part of a coordinated effort to address this class of speculative execution side-channel attacks.

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What to do

Description

AI analysisMachine-generated, updated 13 Nov 2026, 18:31 UTC

Technical details

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