CVE-2026-81387

MEDIUMPre-NVD 5.55.5—
EchelonGraph scoreHIGH confidence

Score 5.5 from GitHub Security Advisory published 2026-09-08. the CNA's CVSS baseline 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
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.

Exposure of sensitive system information to an unauthorized control sphere in Microsoft Office Excel 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
35%
KEV
Not listed

Published

September 8, 2026

Last Modified

September 18, 2026

Advisory Details (1)

Auto-updated Sep 9, 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-2026-81387

Vendor Advisories for CVE-2026-81387(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 41× in last 7d / 78× 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.

  1. 2026-09-18 20:51 UTCEG score recompute
  2. 2026-09-18 20:51 UTCVendor advisory
  3. 2026-09-18 20:50 UTCGHSA enrichment
  4. 2026-09-18 19:28 UTCEPSS rescore
  5. 2026-09-18 14:01 UTCVendor advisory
  6. 2026-09-18 14:01 UTCGHSA enrichment
  7. 2026-09-17 23:24 UTCEG score recompute
  8. 2026-09-17 23:24 UTCVendor advisory
  9. 2026-09-17 23:24 UTCGHSA enrichment
  10. 2026-09-17 20:30 UTCEG score recompute
  11. 2026-09-17 20:30 UTCVendor advisory
  12. 2026-09-17 20:30 UTCGHSA enrichment
  13. 2026-09-17 20:05 UTCEG score recompute
  14. 2026-09-17 20:05 UTCVendor advisory
  15. 2026-09-17 20:05 UTCGHSA enrichment
  16. 2026-09-16 22:06 UTCVendor advisory
  17. 2026-09-16 22:06 UTCGHSA enrichment
  18. 2026-09-16 21:14 UTCEG score recompute
  19. 2026-09-16 21:14 UTCVendor advisory
  20. 2026-09-16 21:14 UTCGHSA enrichment
  21. 2026-09-16 14:08 UTCEPSS rescore
  22. 2026-09-16 05:15 UTCEPSS rescore
  23. 2026-09-15 22:51 UTCVendor advisory
  24. 2026-09-15 22:51 UTCGHSA enrichment
  25. 2026-09-15 17:46 UTCEG score recompute
Show 53 more
  1. 2026-09-15 17:46 UTCVendor advisory
  2. 2026-09-15 17:46 UTCGHSA enrichment
  3. 2026-09-15 03:12 UTCEPSS rescore
  4. 2026-09-15 03:12 UTCEPSS rescore
  5. 2026-09-14 23:03 UTCVendor advisory
  6. 2026-09-14 23:02 UTCGHSA enrichment
  7. 2026-09-14 17:33 UTCVendor advisory
  8. 2026-09-14 17:33 UTCGHSA enrichment
  9. 2026-09-14 17:05 UTCVendor advisory
  10. 2026-09-14 17:05 UTCGHSA enrichment
  11. 2026-09-13 18:54 UTCEG score recompute
  12. 2026-09-13 18:54 UTCVendor advisory
  13. 2026-09-13 18:54 UTCGHSA enrichment
  14. 2026-09-12 20:39 UTCEG score recompute
  15. 2026-09-12 20:39 UTCVendor advisory
  16. 2026-09-12 20:39 UTCGHSA enrichment
  17. 2026-09-11 22:29 UTCVendor advisory
  18. 2026-09-11 22:29 UTCGHSA enrichment
  19. 2026-09-11 19:57 UTCVendor advisory
  20. 2026-09-11 19:57 UTCGHSA enrichment
  21. 2026-09-11 16:56 UTCEG score recompute
  22. 2026-09-11 16:56 UTCVendor advisory
  23. 2026-09-11 16:56 UTCGHSA enrichment
  24. 2026-09-11 14:53 UTCEPSS rescore
  25. 2026-09-11 14:53 UTCEPSS rescore
  26. 2026-09-10 23:23 UTCGHSA enrichment
  27. 2026-09-10 19:55 UTCEG score recompute
  28. 2026-09-10 19:55 UTCGHSA enrichment
  29. 2026-09-09 21:44 UTCVendor advisory
  30. 2026-09-09 21:44 UTCGHSA enrichment
  31. 2026-09-09 19:56 UTCEG score recompute
  32. 2026-09-09 19:56 UTCVendor advisory
  33. 2026-09-09 19:56 UTCGHSA enrichment
  34. 2026-09-09 12:05 UTCEG score recompute
  35. 2026-09-09 12:05 UTCVendor advisory
  36. 2026-09-09 12:05 UTCGHSA enrichment
  37. 2026-09-08 23:53 UTCEG score recompute
  38. 2026-09-08 23:53 UTCVendor advisory
  39. 2026-09-08 23:53 UTCGHSA enrichment
  40. 2026-09-08 20:38 UTCEG score recompute
  41. 2026-09-08 20:38 UTCGHSA enrichment
  42. 2026-09-08 20:15 UTCEG score recompute
  43. 2026-09-08 20:15 UTCGHSA enrichment
  44. 2026-09-08 19:37 UTCEG score recompute
  45. 2026-09-08 19:37 UTCGHSA enrichment
  46. 2026-09-08 18:51 UTCEG score recompute
  47. 2026-09-08 18:51 UTCGHSA enrichment
  48. 2026-09-08 18:36 UTCEG score recompute
  49. 2026-09-08 18:36 UTCVendor advisory
  50. 2026-09-08 18:36 UTCGHSA enrichment
  51. 2026-09-08 17:34 UTCEG score recompute
  52. 2026-09-08 17:34 UTCVendor advisory
  53. 2026-09-08 17:25 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-81387?
CVE-2026-81387 is a medium vulnerability published on September 8, 2026. Exposure of sensitive system information to an unauthorized control sphere in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.
When was CVE-2026-81387 disclosed?
CVE-2026-81387 was first published in the National Vulnerability Database on September 8, 2026, with the most recent update on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-81387 actively exploited?
CVE-2026-81387 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 65.0% of all scored CVEs.
What is the CVSS score of CVE-2026-81387?
CVE-2026-81387 has a CVSS v4.0 base score of 5.5 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-81387?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-81387, 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-2026-81387

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