Back to CVE records
High 8.8Known exploited (CISA KEV)Published Feb 14, 2023
CVE-2023-21529Microsoft Exchange Server Remote Code Execution Vulnerability
Updated under an hour ago ()
Does this affect you?
It affects Microsoft Exchange Server 2013 Cumulative Update 23 and 4 other products. Add what you run to find out whether that includes you.
CISA lists it as known exploited since Apr 13, 2026; federal agencies had to remediate by Apr 27, 2026, and it is known to be used in ransomware. Treat that date as your deadline.
Do this next
Start free and add your stack
Free account, 1 product
Microsoft Exchange Server Remote Code Execution Vulnerability
- CVSS
- 8.8 HIGH (v3.1, CNA)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
- Weakness (CWE)
- CWE-502
- Known exploited
- Added to CISA KEV Apr 13, 2026; federal remediation due Apr 27, 2026; known ransomware useApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- EPSS (exploitation in the next 30 days)
- 59.29% (percentile 99)
- Assigned by
- microsoft
- NVD analysis
- Analyzed
- Record last updated
- Aug 19, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Microsoft Microsoft Exchange Server 2013 Cumulative Update 23 microsoft:exchange_server_2013_cumulative_update_23 (from the name) | from 15.00.0 before 15.00.1497.047 | CNA record |
Microsoft Microsoft Exchange Server 2016 Cumulative Update 23 microsoft:exchange_server_2016_cumulative_update_23 (from the name) | from 15.01.0 before 15.01.2507.021 | CNA record |
Microsoft Microsoft Exchange Server 2019 Cumulative Update 11 microsoft:exchange_server_2019_cumulative_update_11 (from the name) | from 15.02.0 before 15.02.0986.041 | CNA record |
Microsoft Microsoft Exchange Server 2019 Cumulative Update 12 microsoft:exchange_server_2019_cumulative_update_12 (from the name) | from 15.02.0 before 15.02.1118.025 | CNA record |
microsoft exchange_server microsoft:exchange_server | 2013; 2016; 2019; 2019 | NVD |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529vendor-advisory, patch
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-21529us-government-resource
- https://www.microsoft.com/en-us/security/blog/2026/04/06/storm-1175-focuses-gaze-on-vulnerable-web-facing-assets-in-high-tempo-medusa-ransomware-operations/technical-description
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.