CVE-2026-78515

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory published 2026-09-08. the CNA's CVSS baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
Trending — 4 sources updated this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 6.5Exploit: None knownExposed: 0

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

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.

CVSS v3
6.5
EG Score
6.5(high)
EG Risk
30(Track)
EG Risk 30/100SSVC: 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
Severity65% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
59%
KEV
Not listed

Published

September 8, 2026

Last Modified

September 24, 2026

Advisory Details (1)

Auto-updated Sep 8, 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-2026-78515

Vendor Advisories for CVE-2026-78515(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 37× in last 7d / 105× 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 105 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-78515?
CVE-2026-78515 is a medium vulnerability published on September 8, 2026. Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.
When was CVE-2026-78515 disclosed?
CVE-2026-78515 was first published in the National Vulnerability Database on September 8, 2026, with the most recent update on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-78515 actively exploited?
CVE-2026-78515 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 41.4% of all scored CVEs.
What is the CVSS score of CVE-2026-78515?
CVE-2026-78515 has a CVSS v4.0 base score of 6.5 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-78515?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-78515, 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-2026-78515

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