CVE-2021-34470

FAQ

Why are the links to the download center and KB articles for the CVE pointing to the June Cumulative Update for Exchange Server 2019 and Exchange Server 2016?

This vulnerability involved a schema change and therefore needed to be fixed in a cumulative update. For these versions, this vulnerability was addressed in the cumulative updated released on June 29, 2021.

According to the CVSS metric, the attack vector is adjacent (AV:A). What does that mean for this vulnerability?

This vulnerability's attack is limited at the protocol level to a logically adjacent topology. This means it cannot simply be done across the internet, but instead needs something specific tied to the target. Good examples would include the same shared physical network (such as Bluetooth or IEEE 802.11), logical network (local IP subnet), or from within a secure or otherwise limited administrative domain (MPLS, secure VPN to an administrative network zone). This is common to many attacks that require man-in-the-middle type setups or that rely on initially gaining a foothold in another environment.