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Critical severity10.0NVD Advisory· Published Jul 24, 2026· Updated Jul 29, 2026

CVE-2026-56191

CVE-2026-56191

Description

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

Affected products

2

Microsoft/Exchange Online2 versions
cpe:2.3:a:microsoft:exchange_online:-:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:a:microsoft:exchange_online:-:*:*:*:*:*:*:*
- (no CPE)

Patches

Vulnerability mechanics

References

1

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56191nvdVendor Advisory

News mentions

0

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