AI and data stack advisories

Severe, 6 weeks1496Projects326

1496 severe, 6 weeks · 326 projects

MicrosoftCVE-2026-56191

Microsoft Exchange Online: improper authentication

Microsoft

CVE-2026-56191 · Published Jul 24, 2026 · updated Jul 29, 2026

Critical10.0
No fix yet
Microsoft advisory

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

Affected versions

PackageAffectedFixed in
Microsoft Exchange Online
Product
all versionsNo fix yet
Details and references
CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Severity from
the vendor (its own CVE record or advisory)
Weakness
CWE-287

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