CVE-2023-21529 kev+ ransomware in the critical feed json
Microsoft Exchange Server Remote Code Execution Vulnerability
published 2023-02-14 3 y ago modified 2026-08-19 2 mo ago also EUVD-2023-25697
- cvss
- 8.8
- version 3.1, CNA
- cisa kev
- Exploited
- added 2026-04-13, used in ransomware
- epss
- 59.3%
- EPSS 59.3% chance of exploitation in 30 days, percentile 99.1%
- public exploits
- 0
- none known
Summary
Microsoft Exchange Server Remote Code Execution Vulnerability
Patch / fix
cisa required action Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Microsoft Microsoft Exchange Server 2013 Cumulative Update 23 15.00.1497.047
- Microsoft Microsoft Exchange Server 2016 Cumulative Update 23 15.01.2507.021
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 11 15.02.0986.041
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 12 15.02.1118.025
Timeline
- Published
- CISA SSVC: exploitation active
- Added to CISA KEV
- CISA patch deadline
Known exploited
- Added
- 6 mo ago
- Patch by
- 2026-04-27 (6 mo ago)
- Ransomware
- Known to be used in ransomware campaigns
- Required action
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Vendor, product
- Microsoft, Exchange Server
- CISA name
- Microsoft Exchange Server Deserialization of Untrusted Data Vulnerability
CISA SSVC
- Exploitation
- Active, exploited in the wild
- Automatable
- no
- Technical impact
- total
- Assessed
- 3 y ago
Exploit prediction
59.29% chance of exploitation in the next 30 days, higher than 99.1% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C |
| CNA | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected products
- Microsoft Microsoft Exchange Server 2013 Cumulative Update 23
- Microsoft Microsoft Exchange Server 2016 Cumulative Update 23
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 11
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 12
Classification
- Weakness
-
- CWE-502 Deserialization of Untrusted Data
- Technology feeds
References
-
msrc.microsoft.com
/update-guide/vulnerability/CVE-2023-21529
vendor-advisory, patch
-
microsoft.com
/en-us/security/blog/2026/04/06/storm-1175-focuses-gaze-on-vulnerable-web-facing-assets-in-high-tempo-medusa-r
vendor-advisory, technical-description
-
cisa.gov
/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-21529
government-resource, us-government-resource
Sources
- CVE List CVE-2023-21529
- NVD CVE-2023-21529
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