Microsoft Exchange Server vulnerabilities

256 CVEs affecting Microsoft Exchange Server, 20 known to be exploited (CISA KEV), with EPSS scores. Latest: CVE-2026-96940, published 2026-10-02.

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Known exploited (CISA KEV) first, then by EPSS exploit probability.

• CVE-2021-34473: Microsoft Exchange Server Remote Code Execution Vulnerability, published 2021-07-14. Critical severity, CVSS 9.1. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 100% chance of exploitation in the next 30 days. Microsoft Exchange Server Remote Code Execution Vulnerability
• CVE-2021-26855: Microsoft Exchange Server Remote Code Execution Vulnerability, published 2021-03-03. Critical severity, CVSS 9.1. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 100% chance of exploitation in the next 30 days. Microsoft Exchange Server Remote Code Execution Vulnerability
• CVE-2021-34523: Microsoft Exchange Server Privilege Escalation Vulnerability, published 2021-07-14. Critical severity, CVSS 9.0. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 100% chance of exploitation in the next 30 days. Microsoft Exchange Server Elevation of Privilege Vulnerability
• CVE-2022-41082: Microsoft Exchange Server Remote Code Execution Vulnerability, published 2022-10-03. High severity, CVSS 8.0. Actively exploited: in CISA KEV since 2022-09-30. EPSS: 100% chance of exploitation in the next 30 days. Microsoft Exchange Server Remote Code Execution Vulnerability
• CVE-2020-0688: Microsoft Exchange Server Validation Key Remote Code Execution Vulnerability, published 2020-02-11. High severity, CVSS 8.8. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 100% chance of exploitation in the next 30 days. A remote code execution vulnerability exists in Microsoft Exchange software when the software fails to properly handle objects in memory, aka 'Microsoft Exchange Memory Corruption Vulnerability'.
• CVE-2022-41040: Microsoft Exchange Server Server-Side Request Forgery Vulnerability, published 2022-10-03. High severity, CVSS 8.8. Actively exploited: in CISA KEV since 2022-09-30. EPSS: 100% chance of exploitation in the next 30 days. Microsoft Exchange Server Elevation of Privilege Vulnerability
• CVE-2021-27065: Microsoft Exchange Server Remote Code Execution Vulnerability, published 2021-03-03. High severity, CVSS 7.8. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 99.9% chance of exploitation in the next 30 days. Microsoft Exchange Server Remote Code Execution Vulnerability
• CVE-2021-31207: Microsoft Exchange Server Security Feature Bypass Vulnerability, published 2021-05-11. Medium severity, CVSS 6.6. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 99.8% chance of exploitation in the next 30 days. Microsoft Exchange Server Security Feature Bypass Vulnerability
• CVE-2021-33766: Microsoft Exchange Server Information Disclosure, published 2021-07-14. High severity, CVSS 7.3. Actively exploited: in CISA KEV since 2022-01-18. EPSS: 98.2% chance of exploitation in the next 30 days. Microsoft Exchange Server Information Disclosure Vulnerability
• CVE-2021-26857: Microsoft Exchange Server Remote Code Execution Vulnerability, published 2021-03-03. High severity, CVSS 7.8. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 95.8% chance of exploitation in the next 30 days. Microsoft Exchange Server Remote Code Execution Vulnerability

Latest

• CVE-2026-96940, published 2026-10-02. High severity, CVSS 8.8. EPSS: 0.5% chance of exploitation in the next 30 days. Weak authentication in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
• CVE-2026-69641, published 2026-09-08. Critical severity, CVSS 9.1. EPSS: 0.9% chance of exploitation in the next 30 days. Missing authorization in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
• CVE-2026-69382, published 2026-09-08. Medium severity, CVSS 5.9. EPSS: 0.5% chance of exploitation in the next 30 days. Use of a broken or risky cryptographic algorithm in Microsoft Exchange Server allows an unauthorized attacker to disclose information over a network.
• CVE-2026-69380, published 2026-09-08. High severity, CVSS 8.1. EPSS: 0.7% chance of exploitation in the next 30 days. Missing authorization in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
• CVE-2026-69378, published 2026-09-08. High severity, CVSS 7.5. EPSS: 1.2% chance of exploitation in the next 30 days. Uncontrolled recursion in Microsoft Exchange Server allows an unauthorized attacker to deny service over a network.
• CVE-2026-69375, published 2026-09-08. Medium severity, CVSS 6.5. EPSS: 0.6% chance of exploitation in the next 30 days. Authorization bypass through user-controlled key in Microsoft Exchange Server allows an authorized attacker to perform tampering over a network.
• CVE-2026-69361, published 2026-09-08. Medium severity, CVSS 6.5. EPSS: 0.8% chance of exploitation in the next 30 days. Server-side request forgery (ssrf) in Microsoft Exchange Server allows an authorized attacker to perform spoofing over a network.
• CVE-2026-69356, published 2026-09-08. Critical severity, CVSS 9.3. EPSS: 0.8% chance of exploitation in the next 30 days. Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
• CVE-2026-69355, published 2026-09-08. High severity, CVSS 8.8. EPSS: 0.9% chance of exploitation in the next 30 days. External control of file name or path in Microsoft Exchange Server allows an authorized attacker to execute code over a network.
• CVE-2026-55007, published 2026-09-08. High severity, CVSS 8.1. EPSS: 0.7% chance of exploitation in the next 30 days. Double free in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.