CVE-2026-78518

HIGHPre-NVD 8.88.8—
EchelonGraph scoreHIGH confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-09-08. 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.

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code 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
57%
KEV
Not listed

Published

September 8, 2026

Last Modified

September 18, 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-2026-78518

Vendor Advisories for CVE-2026-78518(2)

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

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 52× in last 7d / 98× 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. 2026-09-20 10:56 UTCVendor advisory
  2. 2026-09-20 10:56 UTCGHSA enrichment
  3. 2026-09-19 22:24 UTCEG score recompute
  4. 2026-09-19 22:24 UTCVendor advisory
  5. 2026-09-19 22:24 UTCGHSA enrichment
  6. 2026-09-19 09:52 UTCVendor advisory
  7. 2026-09-19 09:52 UTCGHSA enrichment
  8. 2026-09-18 21:07 UTCEG score recompute
  9. 2026-09-18 21:07 UTCVendor advisory
  10. 2026-09-18 21:07 UTCGHSA enrichment
  11. 2026-09-18 19:28 UTCEPSS rescore
  12. 2026-09-18 14:13 UTCVendor advisory
  13. 2026-09-18 14:13 UTCGHSA enrichment
  14. 2026-09-18 11:40 UTCVendor advisory
  15. 2026-09-18 11:40 UTCGHSA enrichment
  16. 2026-09-17 23:08 UTCEG score recompute
  17. 2026-09-17 23:08 UTCVendor advisory
  18. 2026-09-17 23:08 UTCGHSA enrichment
  19. 2026-09-17 20:30 UTCEG score recompute
  20. 2026-09-17 20:30 UTCVendor advisory
  21. 2026-09-17 20:30 UTCGHSA enrichment
  22. 2026-09-17 19:55 UTCEG score recompute
  23. 2026-09-17 19:55 UTCVendor advisory
  24. 2026-09-17 19:55 UTCGHSA enrichment
  25. 2026-09-17 10:48 UTCVendor advisory
Show 73 more
  1. 2026-09-17 10:48 UTCGHSA enrichment
  2. 2026-09-16 22:13 UTCEG score recompute
  3. 2026-09-16 22:13 UTCVendor advisory
  4. 2026-09-16 22:13 UTCGHSA enrichment
  5. 2026-09-16 14:08 UTCEPSS rescore
  6. 2026-09-16 11:20 UTCEG score recompute
  7. 2026-09-16 11:20 UTCVendor advisory
  8. 2026-09-16 11:20 UTCGHSA enrichment
  9. 2026-09-16 05:15 UTCEPSS rescore
  10. 2026-09-15 22:48 UTCVendor advisory
  11. 2026-09-15 22:48 UTCGHSA enrichment
  12. 2026-09-15 18:01 UTCVendor advisory
  13. 2026-09-15 18:01 UTCGHSA enrichment
  14. 2026-09-15 11:30 UTCEG score recompute
  15. 2026-09-15 11:30 UTCVendor advisory
  16. 2026-09-15 11:30 UTCGHSA enrichment
  17. 2026-09-15 03:12 UTCEPSS rescore
  18. 2026-09-15 03:12 UTCEPSS rescore
  19. 2026-09-14 22:58 UTCVendor advisory
  20. 2026-09-14 22:58 UTCGHSA enrichment
  21. 2026-09-14 17:50 UTCVendor advisory
  22. 2026-09-14 17:50 UTCGHSA enrichment
  23. 2026-09-14 13:41 UTCVendor advisory
  24. 2026-09-14 13:41 UTCGHSA enrichment
  25. 2026-09-14 01:08 UTCEG score recompute
  26. 2026-09-14 01:08 UTCVendor advisory
  27. 2026-09-14 01:08 UTCGHSA enrichment
  28. 2026-09-13 12:37 UTCVendor advisory
  29. 2026-09-13 12:37 UTCGHSA enrichment
  30. 2026-09-13 00:05 UTCEG score recompute
  31. 2026-09-13 00:05 UTCVendor advisory
  32. 2026-09-13 00:05 UTCGHSA enrichment
  33. 2026-09-12 11:33 UTCVendor advisory
  34. 2026-09-12 11:33 UTCGHSA enrichment
  35. 2026-09-11 23:01 UTCVendor advisory
  36. 2026-09-11 23:00 UTCGHSA enrichment
  37. 2026-09-11 19:44 UTCVendor advisory
  38. 2026-09-11 19:44 UTCGHSA enrichment
  39. 2026-09-11 17:04 UTCEG score recompute
  40. 2026-09-11 17:04 UTCVendor advisory
  41. 2026-09-11 17:04 UTCGHSA enrichment
  42. 2026-09-11 14:53 UTCEPSS rescore
  43. 2026-09-11 14:53 UTCEPSS rescore
  44. 2026-09-11 12:10 UTCEG score recompute
  45. 2026-09-11 12:10 UTCGHSA enrichment
  46. 2026-09-10 23:38 UTCGHSA enrichment
  47. 2026-09-10 10:59 UTCEG score recompute
  48. 2026-09-10 10:59 UTCGHSA enrichment
  49. 2026-09-09 22:25 UTCGHSA enrichment
  50. 2026-09-09 20:12 UTCEG score recompute
  51. 2026-09-09 20:12 UTCVendor advisory
  52. 2026-09-09 20:12 UTCGHSA enrichment
  53. 2026-09-09 12:05 UTCVendor advisory
  54. 2026-09-09 12:05 UTCGHSA enrichment
  55. 2026-09-09 10:30 UTCEG score recompute
  56. 2026-09-09 10:30 UTCVendor advisory
  57. 2026-09-09 10:30 UTCGHSA enrichment
  58. 2026-09-09 10:19 UTCVendor advisory
  59. 2026-09-09 10:19 UTCGHSA enrichment
  60. 2026-09-09 04:35 UTCVendor advisory
  61. 2026-09-09 04:35 UTCGHSA enrichment
  62. 2026-09-09 04:08 UTCEG score recompute
  63. 2026-09-09 04:08 UTCVendor advisory
  64. 2026-09-09 04:07 UTCGHSA enrichment
  65. 2026-09-09 00:08 UTCEG score recompute
  66. 2026-09-09 00:08 UTCVendor advisory
  67. 2026-09-09 00:08 UTCGHSA enrichment
  68. 2026-09-08 19:42 UTCGHSA enrichment
  69. 2026-09-08 18:58 UTCEG score recompute
  70. 2026-09-08 18:58 UTCGHSA enrichment
  71. 2026-09-08 17:56 UTCEG score recompute
  72. 2026-09-08 17:56 UTCVendor advisory
  73. 2026-09-08 17:25 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-78518?
CVE-2026-78518 is a high vulnerability published on September 8, 2026. Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.
When was CVE-2026-78518 disclosed?
CVE-2026-78518 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-2026-78518 actively exploited?
CVE-2026-78518 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 43.1% of all scored CVEs.
What is the CVSS score of CVE-2026-78518?
CVE-2026-78518 has a CVSS v4.0 base score of 8.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-78518?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-78518, 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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