CVE-2026-55039

HIGHPre-NVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-07-14. the CNA's CVSS baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
Trending — 4 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: None knownExposed: 0

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

Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: 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
Severity78% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
40%
KEV
Not listed

Published

July 14, 2026

Last Modified

September 17, 2026

Advisory Details (1)

Auto-updated Jul 14, 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-2026-55039

Vendor Advisories for CVE-2026-55039(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 15× in last 7d / 101× 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 290 total refreshes for this CVE.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-17 23:02 UTCEG score recompute
  3. 2026-09-17 23:02 UTCVendor advisory
  4. 2026-09-17 23:02 UTCGHSA enrichment
  5. 2026-09-17 19:31 UTCEPSS rescore
  6. 2026-09-16 14:08 UTCEPSS rescore
  7. 2026-09-16 05:15 UTCEPSS rescore
  8. 2026-09-15 03:11 UTCEPSS rescore
  9. 2026-09-13 23:19 UTCEG score recompute
  10. 2026-09-13 23:19 UTCVendor advisory
  11. 2026-09-13 23:19 UTCGHSA enrichment
  12. 2026-09-13 16:47 UTCEPSS rescore
  13. 2026-09-13 07:44 UTCEG score recompute
  14. 2026-09-13 07:44 UTCVendor advisory
  15. 2026-09-13 07:44 UTCGHSA enrichment
  16. 2026-09-12 14:11 UTCVendor advisory
  17. 2026-09-12 14:11 UTCGHSA enrichment
  18. 2026-09-12 01:23 UTCEG score recompute
  19. 2026-09-12 01:23 UTCVendor advisory
  20. 2026-09-12 01:23 UTCGHSA enrichment
  21. 2026-09-11 14:53 UTCEPSS rescore
  22. 2026-09-10 09:35 UTCEPSS rescore
  23. 2026-09-09 22:44 UTCEG score recompute
  24. 2026-09-09 22:44 UTCGHSA enrichment
  25. 2026-09-08 22:01 UTCEPSS rescore
Show 75 more
  1. 2026-09-08 21:10 UTCGHSA enrichment
  2. 2026-09-08 20:26 UTCGHSA enrichment
  3. 2026-09-08 01:21 UTCEG score recompute
  4. 2026-09-08 01:21 UTCVendor advisory
  5. 2026-09-08 01:21 UTCGHSA enrichment
  6. 2026-09-07 16:01 UTCEPSS rescore
  7. 2026-09-06 13:47 UTCEPSS rescore
  8. 2026-09-06 13:38 UTCVendor advisory
  9. 2026-09-06 13:38 UTCGHSA enrichment
  10. 2026-09-05 21:05 UTCEG score recompute
  11. 2026-09-05 21:05 UTCVendor advisory
  12. 2026-09-05 21:05 UTCGHSA enrichment
  13. 2026-09-04 22:51 UTCEG score recompute
  14. 2026-09-04 22:51 UTCVendor advisory
  15. 2026-09-04 22:51 UTCGHSA enrichment
  16. 2026-09-04 05:06 UTCEPSS rescore
  17. 2026-09-02 19:44 UTCEG score recompute
  18. 2026-09-02 19:44 UTCVendor advisory
  19. 2026-09-02 19:44 UTCGHSA enrichment
  20. 2026-09-02 14:12 UTCEPSS rescore
  21. 2026-09-01 13:54 UTCEPSS rescore
  22. 2026-08-31 15:45 UTCVendor advisory
  23. 2026-08-31 15:45 UTCGHSA enrichment
  24. 2026-08-31 07:02 UTCEG score recompute
  25. 2026-08-31 07:02 UTCVendor advisory
  26. 2026-08-31 07:02 UTCGHSA enrichment
  27. 2026-08-30 19:17 UTCEPSS rescore
  28. 2026-08-30 17:26 UTCVendor advisory
  29. 2026-08-30 17:26 UTCGHSA enrichment
  30. 2026-08-30 04:40 UTCEG score recompute
  31. 2026-08-30 04:40 UTCVendor advisory
  32. 2026-08-30 04:40 UTCGHSA enrichment
  33. 2026-08-30 01:22 UTCEPSS rescore
  34. 2026-08-28 22:30 UTCEG score recompute
  35. 2026-08-28 22:30 UTCVendor advisory
  36. 2026-08-28 22:29 UTCGHSA enrichment
  37. 2026-08-28 21:41 UTCEPSS rescore
  38. 2026-08-27 21:30 UTCEG score recompute
  39. 2026-08-27 21:30 UTCVendor advisory
  40. 2026-08-27 21:30 UTCGHSA enrichment
  41. 2026-08-27 14:25 UTCEPSS rescore
  42. 2026-08-27 03:12 UTCEG score recompute
  43. 2026-08-27 03:12 UTCVendor advisory
  44. 2026-08-27 03:12 UTCGHSA enrichment
  45. 2026-08-26 14:46 UTCEPSS rescore
  46. 2026-08-26 14:26 UTCVendor advisory
  47. 2026-08-26 14:26 UTCGHSA enrichment
  48. 2026-08-26 01:20 UTCEG score recompute
  49. 2026-08-26 01:20 UTCVendor advisory
  50. 2026-08-26 01:20 UTCGHSA enrichment
  51. 2026-08-25 13:49 UTCEPSS rescore
  52. 2026-08-25 10:09 UTCVendor advisory
  53. 2026-08-25 10:09 UTCGHSA enrichment
  54. 2026-08-24 21:23 UTCEG score recompute
  55. 2026-08-24 21:23 UTCVendor advisory
  56. 2026-08-24 21:23 UTCGHSA enrichment
  57. 2026-08-24 10:47 UTCEG score recompute
  58. 2026-08-24 10:47 UTCVendor advisory
  59. 2026-08-24 10:47 UTCGHSA enrichment
  60. 2026-08-23 21:57 UTCVendor advisory
  61. 2026-08-23 21:57 UTCGHSA enrichment
  62. 2026-08-23 09:11 UTCEG score recompute
  63. 2026-08-23 09:11 UTCVendor advisory
  64. 2026-08-23 09:11 UTCGHSA enrichment
  65. 2026-08-23 00:19 UTCEPSS rescore
  66. 2026-08-22 20:24 UTCVendor advisory
  67. 2026-08-22 20:24 UTCGHSA enrichment
  68. 2026-08-22 07:38 UTCEG score recompute
  69. 2026-08-22 07:38 UTCVendor advisory
  70. 2026-08-22 07:38 UTCGHSA enrichment
  71. 2026-08-21 23:49 UTCEPSS rescore
  72. 2026-08-21 18:52 UTCGHSA enrichment
  73. 2026-08-21 06:06 UTCEG score recompute
  74. 2026-08-21 06:06 UTCVendor advisory
  75. 2026-08-21 06:06 UTCGHSA enrichment

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-55039?
CVE-2026-55039 is a high vulnerability published on July 14, 2026. Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
When was CVE-2026-55039 disclosed?
CVE-2026-55039 was first published in the National Vulnerability Database on July 14, 2026, with the most recent update on September 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55039 actively exploited?
CVE-2026-55039 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 60.4% of all scored CVEs.
What is the CVSS score of CVE-2026-55039?
CVE-2026-55039 has a CVSS v4.0 base score of 7.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-55039?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55039, 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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