CVE-2026-56191

Severity

CRITICAL

CVSS

10.0

EPSS

0.00667

Risk score

40.23

CISA KEV

PoC

Published

2026-07-24

Modified

2026-08-14

First seen

2026-08-05

Aliases

EUVD-2026-48458, GHSA-W7QH-JVR9-QMX9

Products

Microsoft Exchange Online -, microsoft:exchange_online

Sources

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