PatchTheCVEexchange online vulnerabilities and fixes
Recent CVEs affecting exchange online, with upgrade or downgrade steps. 1 tracked.
Also searched as: exchangeonline.
exchange online has 1 tracked vulnerability, 1 critical. A fixed release or vendor patch exists for 1. Most recent: 2026-07-24. Highest priority: CVE-2026-56191 (score 63/100).
- CVE-2026-56191 CRITICAL 10.0 MITIGATE Improper authentication in Microsoft Exchange Online allows an unauthorized attacker to perform tampering over
FAQ
How do I fix exchange online vulnerabilities?
Open the CVE for your version, check the affected range, then follow the listed action: upgrade to the fixed release, or downgrade or mitigate if no fix exists yet. Commands for each OS are shown on every CVE page.
Is exchange online being exploited right now?
None of the tracked exchange online CVEs are on the CISA Known Exploited Vulnerabilities list at the moment. This is checked every 20 minutes.
Which exchange online CVE should I patch first?
CVE-2026-56191 currently ranks highest (63/100): Improper authentication in Microsoft Exchange Online allows an unauthorized attacker to perform tampering over.