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CVE-2026-56191

10.0 critical SSVC exploitation: none Analyzed
NVD · CVE.org

Improper authentication in Microsoft Exchange Online allows an unauthorized attacker to perform tampering over a network.

Fix

Patch, vendor advisory and mitigation references on NVD 1

Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.

Change history 1

  1. First seenCVSS 10.0 · microsoftNVD modified 2026-10-24 13:10

Affected (CPE criteria) 1

  • cpe:2.3:a:microsoft:exchange_online:-:*:*:*:*:*:*:*

References 1