CVE-2021-31956

CRITICALNVD 7.89.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), 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
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 22%CVSS: 7.8Exploit: cisa kev · ssvc active · epss top5pct · public exploitExposed: 0

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

Windows NTFS 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 PROB
22%
EPSS %ILE
98%
KEV
⚠ Exploited

Published

June 8, 2021

Last Modified

January 13, 2026

Advisory Details (2)

Auto-updated Jun 3, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa, microsoft.
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-2021-31956
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-2021-31956

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 94× in last 7d / 402× 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 1,406 total refreshes for this CVE.

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

Publicly available exploits

(3 references)

Working exploit code is in the public domain (3 GitHub PoCs). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoChoangprod/CVE-2021-31956-POC
    First seen Jun 5, 2023
    Open source ↗
  • GitHub PoCY3A/CVE-2021-31956
    First seen Sep 2, 2022

    Win10 20H2 LPE for CVE-2021-31956

    Open source ↗
  • GitHub PoCaazhuliang/CVE-2021-31956-EXP
    First seen Jan 11, 2022
    Open source ↗

Related CVEs(same vendor + same CWE)

Frequently asked(6)

What is CVE-2021-31956?
CVE-2021-31956 is a critical vulnerability published on June 8, 2021. Windows NTFS Elevation of Privilege Vulnerability
When was CVE-2021-31956 disclosed?
CVE-2021-31956 was first published in the National Vulnerability Database on June 8, 2021, with the most recent update on January 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-31956 actively exploited?
Yes. CISA added CVE-2021-31956 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-2021-31956?
CVE-2021-31956 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-2021-31956?
CVE-2021-31956 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-2021-31956?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-31956, 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-2021-31956

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