BlackTreeIndependent security intelligenceMicrosoft · Microsoft Exchange Server 2016 Cumulative Update 23
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
Fix not verifiedImproper authorization in Microsoft Exchange Server allows an authorized attacker to disclose information over a network.
Improper authorization in Microsoft Exchange Server allows an authorized attacker to disclose information over a network.
The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.
An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
Improper authorization in Microsoft Exchange Server allows an authorized attacker to disclose information over a network.
The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.
An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
CWE-285: Improper Authorization. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:CCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
Operational remediation based on structured source evidence.
Published 9 Jun 2026 · Last source change 25 Aug 2026, 22:43 UTC · CWE-285 · Improper Authorization
Core structured fields are present and their contributing authorities are shown above.
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.