Microsoft Exchange Server 2016 Cumulative Update 18

productUS

A product tracked in the threat graph; the vulnerabilities below are known to affect it.

unpatched

critical

by severity

0critical1high6medium0low

updated 2026-10-28

vulnerabilities (7)

Related CVEs.

sort

ID	severity	EPSS	exploitable	patched	published	affected
CVE-2021-26855US	high7.5OT critical	100.0% (100th)	KEV	15.01.2106.013	2021-03-03	2 versions
CVE-2021-27065US	medium6.8OT critical	99.9% (100th)	KEV	15.01.2106.013	2021-03-03	2 versions
CVE-2021-26857US	medium6.8OT critical	95.8% (100th)	KEV	15.01.2106.013	2021-03-03	2 versions
CVE-2021-26858US	medium6.8OT critical	93.7% (100th)	KEV	15.01.2106.013	2021-03-03	2 versions
CVE-2021-26412US	medium6.5	33.8% (98th)	—	15.01.2106.013	2021-03-03	2 versions
CVE-2021-26854US	medium6.5	24.7% (98th)	—	15.01.2106.013	2021-03-03	2 versions
CVE-2021-27078US	medium6.5	21.6% (98th)	—	15.01.2106.013	2021-03-03	2 versions

The flaw types (CWEs) most of these CVEs share.

CWE-20Improper Input Validation5 CVEs
CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')1 CVEs
CWE-502Deserialization of Untrusted Data1 CVEs
CWE-918Server-Side Request Forgery (SSRF)1 CVEs

Which sources assert this record, and when.

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