boxscore/security
PRODUCT · referenceProducts · latest edition

Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

Microsoft Exchange Server 2016 Cumulative Update 21

Product reference — Microsoft Exchange Server 2016 Cumulative Update 21 by Microsoft · sector: Operating Systems & Platforms. Cumulative disclosure record for this product across the archive.

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Product totals

Disclosures & known-exploited
All-timeYTD
CVEs70
KEV entries20
Rate & severity
KEV/100Med CVSSMed EPSSCHML
28.67.6.13010520

KEV/100 = KEV entries ÷ CVEs × 100. Med CVSS / Med EPSS are medians over this product's disclosures. C/H/M/L = disclosures by CVSS severity band.

Monthly disclosures

Trend (by first-seen month, full archive): █▁▁▁█▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▃▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁

Last 12 months (new CVEs by first-seen day)
MonthNew CVEs
2025-090
2025-100
2025-110
2025-120
2026-010
2026-020
2026-030
2026-040
2026-050
2026-060
2026-070
2026-080

Notable CVEs

Ranked by the published formula: KEV → EPSS → CVSS → CVE ID.

Notable (ranked)
CVECVSSEPSS %ileSeverityKEVFirst seen
CVE-2021-423218.899.8HIGHYES2021-11-17
CVE-2021-311967.298.9HIGHYES2024-08-21
CVE-2021-413496.599.8MEDIUM—2021-11-10
CVE-2021-312067.696.0HIGH—2021-07-14
CVE-2021-423056.594.4MEDIUM—2021-11-10
CVE-2021-344708.090.5HIGH—2021-07-14
CVE-2021-337688.067.9HIGH—2021-07-14

Recent CVEs

Most recently seen
CVECVSSEPSS %ileSeverityKEVFirst seen
CVE-2021-311967.298.9HIGHYES2024-08-21
CVE-2021-423218.899.8HIGHYES2021-11-17
CVE-2021-423056.594.4MEDIUM—2021-11-10
CVE-2021-413496.599.8MEDIUM—2021-11-10
CVE-2021-344708.090.5HIGH—2021-07-14
CVE-2021-337688.067.9HIGH—2021-07-14
CVE-2021-312067.696.0HIGH—2021-07-14

KEV entries

CISA Known Exploited Vulnerabilities (newest addition first)
CVEKEV addedCVSSEPSS %ileSeverity
CVE-2021-311962024-08-217.298.9HIGH
CVE-2021-423212021-11-178.899.8HIGH

Related

Vendor: Microsoft — all products and the full vendor record.

Methodology

A product is a (vendor, product) pair as named in the affected-product data. Rate statistics are arithmetic over published figures. Counts key to first-seen day. Raw counts are not comparable across products; this is a reference page assembled from the public record, not a ranking by our judgment.

Sources. CVE Program (cvelistV5), NVD (NIST), CISA KEV, FIRST EPSS.