Microsoft Exchange Server Information Disclosure Vulnerability
Priority CRITICAL 90Exploited in the wildPublished · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Microsoft. Impact type from Microsoft.
Summary
Microsoft Exchange Server Information Disclosure Vulnerability
Why it matters now
Exploitation Active In CISA KEV since 2022-01-18CISA due date 2022-02-01
EPSS 0.98176 99th percentileScored 2026-11-07
Fix Fixed Microsoft: 1 update
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Active
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Microsoft | Microsoft Exchange Server 2013 Cumulative Update 23 | 15.00.0 to before 15.00.1497.015 | 15.00.1497.015 | Patch available | CNA |
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 19 | 15.01.0 to before 15.01.2176.012 | 15.01.2176.012 | Patch available | CNA |
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 20 | 15.01.0 to before 15.01.2242.008 | 15.01.2242.008 | Patch available | CNA |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 8 | 15.02.0 to before 15.02.0792.013 | 15.02.0792.013 | Patch available | CNA |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 9 | 15.02.0 to before 15.02.0858.010 | 15.02.0858.010 | Patch available | CNA |
- Microsoft Exchange Server 2013 Cumulative Update 23 VendorMicrosoft Affected 15.00.0 to before 15.00.1497.015 Fixed in 15.00.1497.015 Patch available CNA
- Microsoft Exchange Server 2016 Cumulative Update 19 VendorMicrosoft Affected 15.01.0 to before 15.01.2176.012 Fixed in 15.01.2176.012 Patch available CNA
- Microsoft Exchange Server 2016 Cumulative Update 20 VendorMicrosoft Affected 15.01.0 to before 15.01.2242.008 Fixed in 15.01.2242.008 Patch available CNA
- Microsoft Exchange Server 2019 Cumulative Update 8 VendorMicrosoft Affected 15.02.0 to before 15.02.0792.013 Fixed in 15.02.0792.013 Patch available CNA
- Microsoft Exchange Server 2019 Cumulative Update 9 VendorMicrosoft Affected 15.02.0 to before 15.02.0858.010 Fixed in 15.02.0858.010 Patch available CNA
CPE configurations NVD · 5
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:* | 2013 cumulative_update_23 | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:* | 2016 cumulative_update_19 | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_20:*:*:*:*:*:* | 2016 cumulative_update_20 | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:* | 2019 cumulative_update_8 | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_9:*:*:*:*:*:* | 2019 cumulative_update_9 | Vulnerable | Microsoft |
- cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:* Versions 2013 cumulative_update_23 Vulnerable ·Microsoft
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:* Versions 2016 cumulative_update_19 Vulnerable ·Microsoft
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_20:*:*:*:*:*:* Versions 2016 cumulative_update_20 Vulnerable ·Microsoft
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:* Versions 2019 cumulative_update_8 Vulnerable ·Microsoft
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_9:*:*:*:*:*:* Versions 2019 cumulative_update_9 Vulnerable ·Microsoft
Remediation
Microsoft 1 update
- Security Update
- Microsoft Exchange Server 2013 Cumulative Update 23 15.00.1497.015
- Microsoft Exchange Server 2016 Cumulative Update 19 15.01.2176.012
- Microsoft Exchange Server 2016 Cumulative Update 20 15.01.2242.008
- Microsoft Exchange Server 2019 Cumulative Update 8 15.02.0792.013
- Microsoft Exchange Server 2019 Cumulative Update 9 15.02.0858.010
Vendor assessments
Microsoft
Microsoft's page for this CVE →
- Impact
- Information Disclosure
- Exploited
- No
- Publicly disclosed
- No
- Exploitability
- Exploitation Less Likely
Timeline
- 2022-01-18 Added to CISA KEV
- 2026-10-02 Threatist record created from CVE-2021-33766
- 2026-10-03 Alias added: GHSA-f9f4-96j3-5mvr
References
More Microsoft Exchange Server vulnerabilities
- TI-2024-14170 Microsoft Exchange Server Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 9.8
- TI-2022-19610 Microsoft Exchange Server Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 9.8
- TI-2021-13547 Microsoft Exchange Server Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 9.8
- TI-2021-13502 Microsoft Exchange Server Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
- TI-2021-08465 Microsoft Exchange Server Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
- TI-2023-07929 Microsoft Exchange Server Remote Code Execution Vulnerability KEVCVSS 3.1HIGH 8.8
Sources
- CVE-2021-33766 · CVE Program
- CVE-2021-33766 · NVD
- CISA Known Exploited Vulnerabilities
- FIRST EPSS
- GHSA-f9f4-96j3-5mvr · GitHub Advisory Database · CC BY 4.0
- CVE-2021-33766 · Microsoft Security Update Guide
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences