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CVE-2026-48579: exchange online vulnerability
CVE-2026-48579: critical vulnerability affecting exchange online. Check CVSS, KEV status, business impact and recommended administrator actions.
- CVSS
- 9.1 CRITICAL
- EPSS
- 59.68%
- Known exploited
- not in KEV
- Product
- exchange online
What is known
Improper authorization in Microsoft Exchange Online allows an unauthorized attacker to disclose information over a network.
Business impact
Successful exploitation of CVE-2026-48579, a critical vulnerability (CVSS 9.1) affecting exchange online, may affect the confidentiality, integrity or availability of the vulnerable environment. The exact impact depends on the installed version, exposed interfaces and deployment configuration.
Recommended administrator action
Confirm whether exchange online is present and compare installed versions with the vendor advisory and NVD record. Apply the vendor patch or documented mitigation; until remediation is complete, reduce exposure of affected interfaces, review relevant logs and monitor for indicators of exploitation. DataHouse can support version verification, managed patching, network exposure reduction, log review and backup validation for dedicated, cloud and colocated environments.