CVE-2021-33739

CRITICALNVD 8.49.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 8.4 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 5 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 7%CVSS: 8.4Exploit: cisa kev · ssvc active · public exploitExposed: 0

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

Microsoft DWM Core Library Elevation of Privilege Vulnerability

CVSS v3
8.4
EG Score
9.0(high)
EG Risk
81(Attend)
EG Risk 81/100SSVC: Attend

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%
Exploitation100% × 40%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
7%
EPSS %ILE
93%
KEV
⚠ Exploited

Published

June 8, 2021

Last Modified

October 30, 2025

Advisory Details (2)

Auto-updated Jun 2, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: microsoft, cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33739
microsoft Patch Available

Security Update Guide - Microsoft Security Response Center

Security Update Guide - Microsoft Security Response Center. Patch available via Microsoft Security Update

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33739

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

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 67× in last 7d / 393× 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.

Showing the most recent 100 of 808 total refreshes for this CVE.

  1. 2026-07-29 11:10 UTCVendor advisory
  2. 2026-07-29 11:10 UTCGHSA enrichment
  3. 2026-07-29 07:20 UTCVendor advisory
  4. 2026-07-29 07:20 UTCGHSA enrichment
  5. 2026-07-29 03:29 UTCVendor advisory
  6. 2026-07-29 03:29 UTCGHSA enrichment
  7. 2026-07-28 23:38 UTCVendor advisory
  8. 2026-07-28 23:38 UTCGHSA enrichment
  9. 2026-07-28 19:48 UTCVendor advisory
  10. 2026-07-28 19:48 UTCGHSA enrichment
  11. 2026-07-28 15:57 UTCEG score recompute
  12. 2026-07-28 15:57 UTCVendor advisory
  13. 2026-07-28 15:57 UTCGHSA enrichment
  14. 2026-07-28 15:33 UTCEPSS rescore
  15. 2026-07-28 12:06 UTCVendor advisory
  16. 2026-07-28 12:06 UTCGHSA enrichment
  17. 2026-07-28 08:15 UTCVendor advisory
  18. 2026-07-28 08:15 UTCGHSA enrichment
  19. 2026-07-28 04:24 UTCVendor advisory
  20. 2026-07-28 04:23 UTCGHSA enrichment
  21. 2026-07-28 00:33 UTCVendor advisory
  22. 2026-07-28 00:33 UTCGHSA enrichment
  23. 2026-07-27 20:43 UTCVendor advisory
  24. 2026-07-27 20:43 UTCGHSA enrichment
  25. 2026-07-27 19:24 UTCCISA KEV update
Show 75 more
  1. 2026-07-27 17:17 UTCCISA KEV update
  2. 2026-07-27 16:52 UTCVendor advisory
  3. 2026-07-27 16:52 UTCGHSA enrichment
  4. 2026-07-27 13:03 UTCVendor advisory
  5. 2026-07-27 13:02 UTCGHSA enrichment
  6. 2026-07-27 09:12 UTCVendor advisory
  7. 2026-07-27 09:12 UTCGHSA enrichment
  8. 2026-07-27 05:22 UTCVendor advisory
  9. 2026-07-27 05:22 UTCGHSA enrichment
  10. 2026-07-27 01:23 UTCVendor advisory
  11. 2026-07-27 01:22 UTCGHSA enrichment
  12. 2026-07-26 21:31 UTCVendor advisory
  13. 2026-07-26 21:31 UTCGHSA enrichment
  14. 2026-07-26 17:40 UTCEG score recompute
  15. 2026-07-26 17:40 UTCVendor advisory
  16. 2026-07-26 17:39 UTCGHSA enrichment
  17. 2026-07-26 14:52 UTCEPSS rescore
  18. 2026-07-26 14:52 UTCEPSS rescore
  19. 2026-07-26 13:49 UTCEG score recompute
  20. 2026-07-26 13:49 UTCVendor advisory
  21. 2026-07-26 13:49 UTCGHSA enrichment
  22. 2026-07-26 09:59 UTCVendor advisory
  23. 2026-07-26 09:59 UTCGHSA enrichment
  24. 2026-07-26 06:09 UTCVendor advisory
  25. 2026-07-26 06:09 UTCGHSA enrichment
  26. 2026-07-26 02:09 UTCEG score recompute
  27. 2026-07-26 02:09 UTCVendor advisory
  28. 2026-07-26 02:09 UTCGHSA enrichment
  29. 2026-07-25 14:15 UTCEPSS rescore
  30. 2026-07-24 14:15 UTCEPSS rescore
  31. 2026-07-23 14:16 UTCEPSS rescore
  32. 2026-07-23 14:16 UTCEPSS rescore
  33. 2026-07-23 02:01 UTCEG score recompute
  34. 2026-07-23 00:07 UTCEG score recompute
  35. 2026-07-23 00:07 UTCVendor advisory
  36. 2026-07-23 00:06 UTCGHSA enrichment
  37. 2026-07-22 22:48 UTCEG score recompute
  38. 2026-07-22 20:15 UTCGHSA enrichment
  39. 2026-07-22 19:40 UTCCISA KEV update
  40. 2026-07-22 16:25 UTCEG score recompute
  41. 2026-07-22 16:25 UTCVendor advisory
  42. 2026-07-22 16:24 UTCGHSA enrichment
  43. 2026-07-22 14:06 UTCEPSS rescore
  44. 2026-07-22 14:06 UTCEPSS rescore
  45. 2026-07-22 12:33 UTCVendor advisory
  46. 2026-07-22 12:33 UTCGHSA enrichment
  47. 2026-07-22 08:43 UTCVendor advisory
  48. 2026-07-22 08:43 UTCGHSA enrichment
  49. 2026-07-22 04:53 UTCVendor advisory
  50. 2026-07-22 04:53 UTCGHSA enrichment
  51. 2026-07-22 01:02 UTCVendor advisory
  52. 2026-07-22 01:02 UTCGHSA enrichment
  53. 2026-07-21 21:13 UTCVendor advisory
  54. 2026-07-21 21:12 UTCGHSA enrichment
  55. 2026-07-21 17:22 UTCEG score recompute
  56. 2026-07-21 17:22 UTCVendor advisory
  57. 2026-07-21 17:22 UTCGHSA enrichment
  58. 2026-07-21 15:22 UTCEPSS rescore
  59. 2026-07-21 15:22 UTCEPSS rescore
  60. 2026-07-21 14:37 UTCCISA KEV update
  61. 2026-07-21 13:31 UTCVendor advisory
  62. 2026-07-21 13:31 UTCGHSA enrichment
  63. 2026-07-21 09:39 UTCVendor advisory
  64. 2026-07-21 09:39 UTCGHSA enrichment
  65. 2026-07-21 05:49 UTCVendor advisory
  66. 2026-07-21 05:49 UTCGHSA enrichment
  67. 2026-07-21 01:59 UTCVendor advisory
  68. 2026-07-21 01:59 UTCGHSA enrichment
  69. 2026-07-20 22:09 UTCVendor advisory
  70. 2026-07-20 22:09 UTCGHSA enrichment
  71. 2026-07-20 18:19 UTCEG score recompute
  72. 2026-07-20 18:19 UTCVendor advisory
  73. 2026-07-20 18:19 UTCGHSA enrichment
  74. 2026-07-20 17:05 UTCEPSS rescore
  75. 2026-07-20 14:28 UTCGHSA enrichment

Publicly available exploits

(2 references)

Working exploit code is in the public domain (2 GitHub PoCs). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCgiwon9977/CVE-2021-33739_PoC_Analysis
    First seen Sep 24, 2021

    CVE-2021-33739 PoC Analysis

    Open source ↗
  • GitHub PoCfreeide2017/CVE-2021-33739-POC
    First seen Jun 9, 2021
    Open source ↗

Related CVEs(same vendor + same CWE)

Frequently asked(6)

What is CVE-2021-33739?
CVE-2021-33739 is a critical vulnerability published on June 8, 2021. Microsoft DWM Core Library Elevation of Privilege Vulnerability
When was CVE-2021-33739 disclosed?
CVE-2021-33739 was first published in the National Vulnerability Database on June 8, 2021, with the most recent update on October 30, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-33739 actively exploited?
Yes. CISA added CVE-2021-33739 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Microsoft Windows. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-33739?
CVE-2021-33739 has a CVSS v3 base score of 8.4 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2021-33739?
CVE-2021-33739 affects Microsoft Windows. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2021-33739?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-33739, 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

Explore the affected products and dependency analysis for CVE-2021-33739

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