CVE-2021-28482

CRITICALNVD 8.89.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because EPSS predicts 83% probability of exploitation within the next 30 days (top 0.4% of all CVEs). NVD baseline CVSS 8.8 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction ≥85%
Sources: epss, ghsa, nvd
Elevated
9.0EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 83%
CISA-KEV: Not listedEPSS PROB: 83%CVSS: 8.8Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Microsoft Exchange Server Remote Code Execution Vulnerability

CVSS v3
8.8
EG Score
9.0(high)
EG Risk
78(Track)
EG Risk 78/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation83% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
83%
EPSS %ILE
100%
KEV
Not listed

Published

April 13, 2021

Last Modified

November 21, 2024

References (2)

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 3× in last 7d / 15× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-20 22:52 UTCEPSS rescore
  2. 2026-08-16 02:11 UTCEPSS rescore
  3. 2026-08-16 02:11 UTCEPSS rescore
  4. 2026-08-13 21:57 UTCEPSS rescore
  5. 2026-08-11 13:38 UTCEPSS rescore
  6. 2026-08-07 16:23 UTCEPSS rescore
  7. 2026-08-04 15:06 UTCEPSS rescore
  8. 2026-08-01 04:13 UTCEPSS rescore
  9. 2026-07-30 16:25 UTCEPSS rescore
  10. 2026-07-30 16:25 UTCEPSS rescore
  11. 2026-07-26 14:52 UTCEPSS rescore
  12. 2026-07-26 14:52 UTCEPSS rescore
  13. 2026-07-24 14:15 UTCEPSS rescore
  14. 2026-07-23 01:59 UTCEG score recompute▲ 0.20
  15. 2026-07-22 22:46 UTCEG score recompute
  16. 2026-07-22 14:06 UTCEPSS rescore
  17. 2026-07-22 14:06 UTCEPSS rescore
  18. 2026-07-21 15:22 UTCEPSS rescore
  19. 2026-07-21 15:22 UTCEPSS rescore
  20. 2026-07-20 17:05 UTCEPSS rescore
  21. 2026-07-16 17:00 UTCEPSS rescore
  22. 2026-07-15 01:58 UTCEPSS rescore
  23. 2026-07-13 06:10 UTCEPSS rescore
  24. 2026-07-09 19:07 UTCEPSS rescore
  25. 2026-07-04 06:29 UTCEPSS rescore
Show 37 more
  1. 2026-07-04 06:29 UTCEPSS rescore
  2. 2026-07-01 15:03 UTCEPSS rescore
  3. 2026-06-28 04:54 UTCEPSS rescore
  4. 2026-06-28 04:54 UTCEPSS rescore
  5. 2026-06-25 13:48 UTCEPSS rescore
  6. 2026-06-25 13:48 UTCEPSS rescore
  7. 2026-06-23 21:31 UTCEPSS rescore
  8. 2026-06-23 21:31 UTCEPSS rescore
  9. 2026-06-18 17:51 UTCEPSS rescore
  10. 2026-06-18 17:51 UTCEPSS rescore
  11. 2026-06-17 17:51 UTCEPSS rescore
  12. 2026-06-15 17:46 UTCEPSS rescore
  13. 2026-06-13 22:58 UTCEPSS rescore
  14. 2026-06-13 22:58 UTCEPSS rescore
  15. 2026-06-12 23:10 UTCEPSS rescore
  16. 2026-06-10 22:16 UTCEPSS rescore
  17. 2026-06-08 14:15 UTCEPSS rescore
  18. 2026-06-07 15:23 UTCEPSS rescore
  19. 2026-06-07 15:23 UTCEPSS rescore
  20. 2026-06-06 13:46 UTCEPSS rescore
  21. 2026-06-06 13:46 UTCEPSS rescore
  22. 2026-06-06 13:46 UTCEPSS rescore
  23. 2026-06-05 22:45 UTCEPSS rescore
  24. 2026-06-05 22:45 UTCEPSS rescore
  25. 2026-06-05 06:09 UTCEPSS rescore
  26. 2026-06-05 06:09 UTCEPSS rescore
  27. 2026-06-02 20:11 UTCEPSS rescore
  28. 2026-06-02 20:11 UTCEPSS rescore
  29. 2026-06-02 20:11 UTCEPSS rescore
  30. 2026-05-31 22:29 UTCEPSS rescore
  31. 2026-05-31 22:29 UTCEPSS rescore
  32. 2026-05-31 00:15 UTCEPSS rescore
  33. 2026-05-27 13:39 UTCEPSS rescore
  34. 2026-05-27 13:39 UTCEPSS rescore
  35. 2026-05-23 08:06 UTCEG score recompute
  36. 2026-05-23 08:06 UTCVendor advisory
  37. 2026-05-23 08:06 UTCGHSA enrichment

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCShadow0ps/CVE-2021-28482-Exchange-POC
    First seen May 3, 2021

    POC from TestANull for CVE-2021-28482 on Exchange Server

    Open source ↗

Frequently asked(5)

What is CVE-2021-28482?
CVE-2021-28482 is a critical vulnerability published on April 13, 2021. Microsoft Exchange Server Remote Code Execution Vulnerability
When was CVE-2021-28482 disclosed?
CVE-2021-28482 was first published in the National Vulnerability Database on April 13, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-28482 actively exploited?
CVE-2021-28482 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 83% probability of exploitation in the next 30 days, which ranks it in the top 0.3% of all scored CVEs.
What is the CVSS score of CVE-2021-28482?
CVE-2021-28482 has a CVSS v3 base score of 8.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
How do I remediate CVE-2021-28482?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-28482, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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