Microsoft Security Updates for Spectre v2

Number: AV18-071
Date: 27 April 2018


The purpose of this advisory is to bring attention to recently released Microsoft updates in regards to mitigation towards Spectre Variant 2.


Two updates have been released by Microsoft in regards to mitigation towards the Spectre Variant 2 “Branch Target Injection” vulnerability. KB4078407 is software-based OS-level mitigation, whereas KB4091666 is for Intel processors only and includes Intel microcode updates needed to mitigate at the hardware level.

Affected Products:

CVE References: CVE-2017-5715

Suggested Action

CCIRC recommends that system administrators test and deploy the vendor-released updates to affected applications accordingly.


Note to Readers

In support of Public Safety's mission to build a safe and resilient Canada, CCIRC's mandate is to help ensure the security and resilience of the vital non-federal government cyber systems that underpin Canada's national security, public safety and economic prosperity. As Canada's computer security incident response team, CCIRC is Canada's national coordination centre for the prevention and mitigation of, preparedness for, response to, and recovery from cyber incidents on non-federal government systems. It does this by providing authoritative advice and support, and coordinating information sharing and incident response.

Please note, CCIRC PGP key has recently been updated.

For general information, please contact Public Safety Canada's Public Affairs division at:

Telephone: 613-944-4875 or 1-800-830-3118
Fax: 613-998-9589

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