CVE-2023-21707
HighMicrosoft Exchange Server Remote Code Execution Vulnerability
Published Feb 23, 2023 · Updated Aug 19, 2026
Key Facts
Patch immediately- CVE-2023-21707 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting Exchange Server (Microsoft), Microsoft Exchange Server 2013 Cumulative Update 23, Microsoft Exchange Server 2016 Cumulative Update 23 and 2 more products.
- It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
- EPSS estimates a 82% probability of exploitation in the next 30 days.
- Fixed versions are available, including Exchange Server 15.00.1497.048, Exchange Server 15.01.2507.023, Exchange Server 15.02.0986.042.
- Brandefense priority: patch immediately, because it is very likely to be exploited soon.
CVSS v3.1
8.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
82%
Higher than 99.6% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
None known
Get the full CVE-2023-21707 brief as a PDF
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Description
Microsoft Exchange Server Remote Code Execution Vulnerability
Affected Products
11 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Exchange ServerMicrosoft | 2013-cumulative_update_23, 2016-cumulative_update_23, 2019-cumulative_update_11, 2019-cumulative_update_12 | 15.02.0986.042 |
| Microsoft Exchange Server 2013 Cumulative Update 23 | >= 15.00.0 | 15.00.1497.048 |
| Microsoft Exchange Server 2016 Cumulative Update 23 | >= 15.01.0 | 15.01.2507.023 |
| Microsoft Exchange Server 2019 Cumulative Update 11 | >= 15.02.0 | 15.02.0986.042 |
| Microsoft Exchange Server 2019 Cumulative Update 12 | >= 15.02.0 | 15.02.1118.026 |
Patched Releases
Exchange Server
15.00.1497.048, 15.01.2507.023, 15.02.0986.042, 15.02.1118.026
Microsoft Exchange Server 2013 Cumulative Update 23
15.00.1497.048
Microsoft Exchange Server 2016 Cumulative Update 23
15.01.2507.023
Microsoft Exchange Server 2019 Cumulative Update 11
15.02.0986.042
Microsoft Exchange Server 2019 Cumulative Update 12
15.02.1118.026
Timeline
Publicly disclosed
Feb 23, 2023
Last updated
Aug 19, 2026
Weakness Type
- CWE-502 Deserialization of Untrusted Data
References
- advisoryhttps://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-0767
- advisoryhttps://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-25728
- advisoryhttps://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-25729
- advisoryhttps://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-25730
- advisoryhttps://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-25732
FAQ
Common Questions.
Microsoft Exchange Server Remote Code Execution Vulnerability
Affected: Exchange Server (Microsoft) versions 2013-cumulative_update_23, 2016-cumulative_update_23, 2019-cumulative_update_11, 2019-cumulative_update_12; Microsoft Exchange Server 2013 Cumulative Update 23 versions >= 15.00.0; Microsoft Exchange Server 2016 Cumulative Update 23 versions >= 15.01.0, among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Exchange Server 15.00.1497.048, Exchange Server 15.01.2507.023, Exchange Server 15.02.0986.042.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.
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