CVE-2026-66810

MEDIUMNVD 5.55.5—
EchelonGraph scoreHIGH confidence

Score 5.5 from GitHub Security Advisory published 2026-08-11. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 4 sources updated this week
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

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

Heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to disclose information locally.

CVSS v3
5.5
EG Score
5.5(high)
EG Risk
25(Track)
EG Risk 25/100SSVC: 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
Severity55% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
20%
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-2026-66810

Vendor Advisories for CVE-2026-66810(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 74× in last 7d / 110× 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 110 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-66810?
CVE-2026-66810 is a medium vulnerability published on August 11, 2026. Heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to disclose information locally.
When was CVE-2026-66810 disclosed?
CVE-2026-66810 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-2026-66810 actively exploited?
CVE-2026-66810 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 79.7% of all scored CVEs.
What is the CVSS score of CVE-2026-66810?
CVE-2026-66810 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-66810?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66810, 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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