CVE-2021-40449

HIGHNVD 7.89.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-17), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 7.8 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
7.8
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS: 74%CVSS: 7.8Exploit: NoneExposed: 0

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

Win32k Elevation of Privilege Vulnerability

CVSS v3
7.8
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
99.4%
KEV
⚠ Exploited

Published

October 13, 2021

Last Modified

October 30, 2025

Advisory Details (3)

Auto-updated Jun 3, 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-2021-40449
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-2021-40449
generic

Packet Storm

http://packetstormsecurity.com/files/164926/Win32k-NtGdiResetDC-Use-After-Free-Local-Privilege-Escalation.html

Weakness Classification(2)

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 63× in last 7d / 354× 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 673 total refreshes for this CVE.

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

Publicly available exploits

(5 references)

Working exploit code is in the public domain (1 Metasploit module) (4 GitHub PoCs). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCKristal-g/CVE-2021-40449_poc
    First seen Nov 7, 2021

    Exploit for CVE-2021-40449

    Open source ↗
  • GitHub PoChakivvi/CVE-2021-40449
    First seen Oct 25, 2021

    LPE exploit for a UAF in Windows (CVE-2021-40449).

    Open source ↗
  • GitHub PoCKaLendsi/CVE-2021-40449-Exploit
    First seen Oct 20, 2021

    windows 10 14393 LPE

    Open source ↗
  • GitHub PoCly4k/CallbackHell
    First seen Oct 16, 2021

    Exploit for CVE-2021-40449 - Win32k Elevation of Privilege Vulnerability (LPE)

    Open source ↗
  • Metasploitexploit/windows/local/cve_2021_40449✓ verified
    First seen Oct 12, 2021

    Win32k NtGdiResetDC Use After Free Local Privilege Elevation

    Open source ↗

Related CVEs(same vendor + same CWE)

Frequently asked(6)

What is CVE-2021-40449?
CVE-2021-40449 is a high vulnerability published on October 13, 2021. Win32k Elevation of Privilege Vulnerability
When was CVE-2021-40449 disclosed?
CVE-2021-40449 was first published in the National Vulnerability Database on October 13, 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-2021-40449 actively exploited?
Yes. CISA added CVE-2021-40449 to the Known Exploited Vulnerabilities catalog on November 17, 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-2021-40449?
CVE-2021-40449 has a CVSS v3 base score of 7.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2021-40449?
CVE-2021-40449 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-2021-40449?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-40449, 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-2021-40449

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