Reference page — cumulative record through Wednesday, October 7, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
Microsoft Exchange Server 2016 Cumulative Update 20
Product reference — Microsoft Exchange Server 2016 Cumulative Update 20 by Microsoft · sector: Operating Systems & Platforms. Cumulative disclosure record for this product across the archive.
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Product totals
| All-time | YTD | |
|---|---|---|
| CVEs | 7 | 0 |
| KEV entries | 5 | 0 |
| KEV/100 | Med CVSS | Med EPSS | C | H | M | L |
|---|---|---|---|---|---|---|
| 71.4 | 7.6 | .9818 | 2 | 4 | 1 | 0 |
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): ▅▁█▁▁▁█▁▅▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▅▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁
| Month | New CVEs |
|---|---|
| 2025-11 | 0 |
| 2025-12 | 0 |
| 2026-01 | 0 |
| 2026-02 | 0 |
| 2026-03 | 0 |
| 2026-04 | 0 |
| 2026-05 | 0 |
| 2026-06 | 0 |
| 2026-07 | 0 |
| 2026-08 | 0 |
| 2026-09 | 0 |
| 2026-10 | 0 |
Notable CVEs
Ranked by the published formula: KEV → EPSS → CVSS → CVE ID.
| CVE | CVSS | EPSS %ile | Severity | KEV | First seen |
|---|---|---|---|---|---|
| CVE-2021-34473 | 9.1 | 100.0 | CRITICAL | YES | 2021-11-03 |
| CVE-2021-34523 | 9.0 | 100.0 | CRITICAL | YES | 2021-11-03 |
| CVE-2021-31207 | 6.6 | 100.0 | MEDIUM | YES | 2021-05-11 |
| CVE-2021-33766 | 7.3 | 99.9 | HIGH | YES | 2022-01-18 |
| CVE-2021-31196 | 7.2 | 99.0 | HIGH | YES | 2024-08-21 |
| CVE-2021-31206 | 7.6 | 96.2 | HIGH | — | 2021-07-14 |
| CVE-2021-33768 | 8.0 | 68.1 | HIGH | — | 2021-07-14 |
Recent CVEs
| CVE | CVSS | EPSS %ile | Severity | KEV | First seen |
|---|---|---|---|---|---|
| CVE-2021-31196 | 7.2 | 99.0 | HIGH | YES | 2024-08-21 |
| CVE-2021-33766 | 7.3 | 99.9 | HIGH | YES | 2022-01-18 |
| CVE-2021-34523 | 9.0 | 100.0 | CRITICAL | YES | 2021-11-03 |
| CVE-2021-34473 | 9.1 | 100.0 | CRITICAL | YES | 2021-11-03 |
| CVE-2021-33768 | 8.0 | 68.1 | HIGH | — | 2021-07-14 |
| CVE-2021-31206 | 7.6 | 96.2 | HIGH | — | 2021-07-14 |
| CVE-2021-31207 | 6.6 | 100.0 | MEDIUM | YES | 2021-05-11 |
KEV entries
| CVE | KEV added | CVSS | EPSS %ile | Severity |
|---|---|---|---|---|
| CVE-2021-31196 | 2024-08-21 | 7.2 | 99.0 | HIGH |
| CVE-2021-33766 | 2022-01-18 | 7.3 | 99.9 | HIGH |
| CVE-2021-31207 | 2021-11-03 | 6.6 | 100.0 | MEDIUM |
| CVE-2021-34523 | 2021-11-03 | 9.0 | 100.0 | CRITICAL |
| CVE-2021-34473 | 2021-11-03 | 9.1 | 100.0 | CRITICAL |
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.
