Microsoft · Security update · June 9, 2026
KB5103212: June 2026 security update
KB5103212, released June 9, 2026, fixes 11 CVEs in Microsoft Exchange Server Subscription Edition RTM. None of them is reported as exploited. Patch Radar priority: Urgent.
Urgent
CVEs closed
11
1 rated Critical
Exploited
0
None reported
Exploitation more likely
1
Microsoft's assessment
Highest EPSS
0.1964
97th percentile
Priority of the 11 CVEs
Patch now 0
Urgent 1
High 7
Routine 3
Applies to
CVEs this fix closes
| Priority | CVE | Component | Impact | CVSS | EPSS | Exploitation |
|---|---|---|---|---|---|---|
| Urgent | CVE-2026-55008 | Microsoft Exchange Server | Spoofing | 9.6 | 0.0086 | More likely |
| High | CVE-2026-55009 | Microsoft Exchange Server | Elevation of Privilege | 7.8 | 0.0251 | Exploitation Unlikely |
| High | CVE-2026-45504 | Microsoft Exchange Server | Elevation of Privilege | 8.8 | 0.0133 | Exploitation Unlikely |
| High | CVE-2026-55005 | Microsoft Exchange Server | Remote Code Execution | 8.8 | 0.0101 | Exploitation Less Likely |
| High | CVE-2026-45583 | Microsoft Exchange Server | Remote Code Execution | 7.5 | 0.0052 | Exploitation Less Likely |
| High | CVE-2026-45503 | Microsoft Exchange Server | Information Disclosure | 8.1 | 0.0045 | Exploitation Unlikely |
| High | CVE-2026-47631 | Microsoft Exchange Server | Spoofing | 8.1 | 0.0035 | Exploitation Less Likely |
| High | CVE-2026-55006 | Microsoft Exchange Server | Elevation of Privilege | 7.8 | 0.0030 | Exploitation Less Likely |
| Routine | CVE-2026-45502 | Microsoft Exchange Server | Information Disclosure | 5.0 | 0.1964 | Exploitation Unlikely |
| Routine | CVE-2026-45501 | Microsoft Exchange Server | Spoofing | 6.5 | 0.0040 | Exploitation Less Likely |
| Routine | CVE-2026-45500 | Microsoft Exchange Server | Spoofing | 6.1 | 0.0038 | Exploitation Less Likely |
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