CVE-2026-55140

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.

Heap-based buffer overflow in Microsoft Office 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-2026-55140

Vendor Advisories for CVE-2026-55140(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 13× 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 308 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55140?
CVE-2026-55140 is a high vulnerability published on July 14, 2026. Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
When was CVE-2026-55140 disclosed?
CVE-2026-55140 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-2026-55140 actively exploited?
CVE-2026-55140 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-2026-55140?
CVE-2026-55140 has a CVSS v4.0 base score of 7.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-55140?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55140, 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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