Microsoft Exchange Server vulnerabilities: known CVEs & security history
Microsoft · Microsoft · 11 tracked CVEs · 0 actively exploited · updated August 2026 · what is a CVE? →
This is the full list of known vulnerabilities (CVEs) across all Microsoft Exchange Server release lines — 11 in total. A CVE here doesn't mean your version is affected — check Microsoft Exchange Server's current status and the safe version to run.
Known Microsoft Exchange Server CVEs
Actively-exploited and most-severe first. Open any CVE for full details.
| CVE | Severity | CVSS | EPSS | Year |
|---|---|---|---|---|
| CVE-2026-55008 | critical | 9.6 | 1% | 2026 |
| CVE-2026-55005 | high | 8.8 | 1% | 2026 |
| CVE-2026-45504 | high | 8.8 | 1% | 2026 |
| CVE-2026-47631 | high | 8.1 | 0% | 2026 |
| CVE-2026-45503 | high | 8.1 | 0% | 2026 |
| CVE-2026-55009 | high | 7.8 | 2% | 2026 |
| CVE-2026-55006 | high | 7.8 | 0% | 2026 |
| CVE-2026-45583 | high | 7.5 | 0% | 2026 |
| CVE-2026-45501 | medium | 6.5 | 0% | 2026 |
| CVE-2026-45500 | medium | 6.1 | 0% | 2026 |
| CVE-2026-45502 | medium | 5 | 20% | 2026 |
Is my Microsoft Exchange Server version affected?
The list above spans every release. To know whether your version is affected — and the minimum safe version to upgrade to — check it directly.
Check your Microsoft Exchange Server version → · Monitor Microsoft Exchange Server for new CVEs →
Microsoft Exchange Server vulnerabilities — frequently asked
How many known vulnerabilities does Microsoft Exchange Server have?
IsItPatched tracks 11 CVEs for Microsoft Exchange Server. 1 is critical-severity and 7 high-severity. These span every release line — what matters is whether the version you run is affected.
Does Microsoft Exchange Server have any actively-exploited vulnerabilities?
None of Microsoft Exchange Server's tracked CVEs are currently in CISA's KEV catalog — but new ones can be added at any time, so keep your version current.
What is the most severe Microsoft Exchange Server vulnerability?
Among tracked issues, CVE-2026-55008 (CRITICAL, CVSS 9.6) ranks highest — a Cross-site scripting (XSS) weakness.
Is Microsoft Exchange Server safe to use?
It depends on the version. The latest supported Microsoft Exchange Server release (15.2.2562.43) clears the known issues; older versions may still be affected. Check the exact version you run for a verdict.
CVE data aggregated from NVD, CISA KEV and EPSS (FIRST.org). Related: Microsoft Exchange Server security status · Microsoft Exchange Server end-of-life · actively-exploited CVEs. Always verify against Microsoft's advisories — see our disclaimer.