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Fencer Vulns
high 8.8

CVE-2023-21706 json

Microsoft Exchange Server Remote Code Execution Vulnerability

published 2023-02-14 3 y ago modified 2026-08-19 2 mo ago also EUVD-2023-25873

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
4.1%
EPSS 4.1% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

Microsoft Exchange Server Remote Code Execution Vulnerability

Patch / fix

  • 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

Exploit prediction

4.06% chance of exploitation in the next 30 days, higher than 90% 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

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.