CVE-2026-45503Important
Microsoft Exchange Server Information Disclosure Vulnerability
Assessment
Improper authorization in Microsoft Exchange Server allows an authorized attacker to disclose information over a network.
- Severity
- Important
- CVSS base score
- 8.1CVSS:3.1/
AV:N/ AC:L/ PR:L/ UI:N/ S:U/ C:H/ I:H/ A:N/ E:U/ RL:O/ RC:C - Impact
- Information Disclosure
- EPSS, next 30 days
- 0.9%Higher than 57% of scored CVEs · FIRST model run 29 Sep 2026 · about EPSS
- Public exploit code
- No Nuclei template lists it
- Exploitability
- Exploitation Unlikely
- Publicly disclosed
- No
- Customer action
- Required: apply the update
- Component
- Microsoft Exchange Server
- Weakness
- CWE-285: Improper Authorization
- Issued by
- Microsoft
- Published
- 9 Jun 2026 · June 2026
- Last revised
- 9 Jun 2026
Updates that fix it
4 KBs| KB | Type | Restart | Applies to | Other CVEs |
|---|---|---|---|---|
| KB5103212 | Security Update | Required | Microsoft Exchange Server Subscription Edition RTM | All CVEs in KB5103212 |
| KB5103213 | Security Update | Required | Microsoft Exchange Server 2019 Cumulative Update 15 | All CVEs in KB5103213 |
| KB5103214 | Security Update | Required | Microsoft Exchange Server 2019 Cumulative Update 14 | All CVEs in KB5103214 |
| KB5103215 | Security Update | Required | Microsoft Exchange Server 2016 Cumulative Update 23 | All CVEs in KB5103215 |