Critical
Microsoft Exchange Online Tampering Vulnerability
Improper authentication in Microsoft Exchange Online allows an unauthorized attacker to perform tampering over a network.
Announced Source revision 1
Original source ↗CVE-2026-56191
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-56191
Microsoft Exchange Online
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "Microsoft",
"product": "Microsoft Exchange Online",
"versions": [
{
"status": "affected",
"version": "-"
}
]
}
]- Related CVEs
- CVE-2026-56191
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #15499 · Revision 1
- Added to Heist Feed
- Publisher date