CVE-2026-54998

HIGHPre-NVD 8.88.8—
EchelonGraph scoreHIGH confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-07-03. 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 weekElevated
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: Elevated riskExposed: 0

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

Incorrect authorization in Microsoft Exchange Online allows an authorized attacker to elevate privileges over a network.

CVSS v3
8.8
EG Score
8.8(high)
EG Risk
56(Track)
EG Risk 56/100SSVC: 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%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
47%
KEV
Not listed

Published

July 2, 2026

Last Modified

July 30, 2026

Advisory Details (1)

Auto-updated Jul 3, 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-2026-54998

Vendor Advisories for CVE-2026-54998(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 / 129× 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 129 total refreshes for this CVE.

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

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCsentinel-aidefense/CVE-2026-54998-exp
    First seen Jul 4, 2026

    CVE-2026-54998 RCE Exploit

    Open source ↗

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-54998?
CVE-2026-54998 is a high vulnerability published on July 2, 2026. Incorrect authorization in Microsoft Exchange Online allows an authorized attacker to elevate privileges over a network.
When was CVE-2026-54998 disclosed?
CVE-2026-54998 was first published in the National Vulnerability Database on July 2, 2026, with the most recent update on July 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-54998 actively exploited?
CVE-2026-54998 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 52.5% of all scored CVEs.
What is the CVSS score of CVE-2026-54998?
CVE-2026-54998 has a CVSS v4.0 base score of 8.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-54998?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-54998, 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-2026-54998

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