Microsoft Exchange Server 2016 Cumulative Update 23 vulnerability

Weak authorization in Microsoft Exchange Server allows an authenticated attacker to elevate privileges over a network.

Published 2 Oct 2026Updated 3 Oct 20261 sources
CVSS 8.8

What happened

Weak authorization in Microsoft Exchange Server allows an authenticated attacker to elevate privileges over a network.

Affected versions

Microsoft Exchange Server 2016 Cumulative Update 23: 15.01.0.0 through before 15.01.2507.075 (custom); 15.02.0.0 through before 15.02.1544.048 (custom); 15.02.0.0 through before 15.02.1748.053 (custom); 15.02.0.0 through before 15.02.2562.053 (custom) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

  • Apply vendor-provided updates or mitigations.
  • Review affected product exposure and access logs.

Public PoC references

No public PoC reference has passed the current publication threshold.