CVE-2026-64921

HIGHPre-NVD 8.88.8—
EchelonGraph scoreHIGH confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-08-11. the CNA's CVSS baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
Trending — 4 sources updated this week
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.8Exploit: None knownExposed: 0

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

Missing authentication for critical function in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.

CVSS v3
8.8
EG Score
8.8(high)
EG Risk
40(Track)
EG Risk 40/100SSVC: 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
Severity88% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
59%
KEV
Not listed

Published

August 11, 2026

Last Modified

August 20, 2026

Advisory Details (1)

Auto-updated Aug 11, 2026
Patch available. Sources: microsoft.
microsoft Patch Available

Security Update Guide - Microsoft Security Response Center

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

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64921

Vendor Advisories for CVE-2026-64921(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 80× in last 7d / 125× 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 125 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-64921?
CVE-2026-64921 is a high vulnerability published on August 11, 2026. Missing authentication for critical function in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.
When was CVE-2026-64921 disclosed?
CVE-2026-64921 was first published in the National Vulnerability Database on August 11, 2026, with the most recent update on August 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-64921 actively exploited?
CVE-2026-64921 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 40.7% of all scored CVEs.
What is the CVSS score of CVE-2026-64921?
CVE-2026-64921 has a CVSS v4.0 base score of 8.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-64921?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-64921, 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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