CVE-2026-62915

This flaw lets someone who already has an account inside your Exchange environment get around a built-in security guard. Think of it like having a less-privileged key to a building that should only open a storage room—but the lock can be bypassed to change things that weren’t meant to be changed. Because it targets Exchange, attackers may be able to modify important settings or data rather than just view them.

This matters if your business runs Microsoft Exchange Server (including Exchange Server 2016 CU23, Exchange Server 2019 CU14/CU15, or Exchange Server Subscription Edition RTM). It’s reachable over the network, but it requires the attacker to already have valid credentials (an authorized user). The risk is highest if an attacker can obtain or abuse a low-privilege account and then reach the Exchange management/authentication endpoints from the network.

This is RED because the issue is an authorization bypass: an attacker with valid (low-privilege) credentials can bypass Exchange security protections over the network. Even without public exploit code or a confirmed CVE-2026-62915 news incident, the presence of a notable attacker actor tied to this patch and the ability to modify server-side security makes it urgent to remediate.