JPCERT-AT-2021-0024
                                                             JPCERT/CC
                                                            2021-05-12

                 <<< JPCERT/CC Alert 2021-05-12 >>>

            Microsoft Releases May 2021 Security Updates

       https://www.jpcert.or.jp/english/at/2021/at210024.html


I. Overview
Microsoft has released May 2021 Security Updates to address the
vulnerabilities in their products. Remote attackers leveraging
these vulnerabilities may be able to execute arbitrary code. It is
recommended to check the information provided by Microsoft and
apply the updates.

    Microsoft Corporation
    May 2021 Security Updates
    https://msrc.microsoft.com/update-guide/en-us/releaseNote/2021-May

    Microsoft Corporation
    Release Notes
    https://msrc.microsoft.com/update-guide/releaseNote

At the time of the update's release, these vulnerabilities were not
confirmed to have been exploited. As for the HTTP Protocol Stack
Remote Code Execution Vulnerability (CVE-2021-31166), which may allow
an unauthenticated attacker to execute code by sending a specially
crafted packet, Microsoft recommends prioritizing the patching of
affected servers.


II. Solution
Please apply the security update programs through Microsoft Update,
Windows Update, etc. as soon as possible.

    Microsoft Update Catalog
    https://www.catalog.update.microsoft.com/

    Windows Update: FAQ
    https://support.microsoft.com/en-us/help/12373/windows-update-faq


III. References
    Microsoft Corporation
    Microsoft Security Updates for May 2021 (Monthly) (Japanese)
    https://msrc-blog.microsoft.com/2021/05/11/202105-security-updates/

    Microsoft Corporation
    HTTP Protocol Stack Remote Code Execution Vulnerability
    https://msrc.microsoft.com/update-guide/en-us/vulnerability/CVE-2021-31166


If you have any information regarding this alert, please contact
JPCERT/CC.

======================================================================
JPCERT Coordination Center (Early Warning Group)
MAIL: ew-info@jpcert.or.jp
https://www.jpcert.or.jp/english/