CVE-2026-54998

HIGHPre-NVD 8.88.8—
EchelonGraph scoreHIGH confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-07-03. a secondary CVSS source baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this weekElevated
8.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 8.8Exploit: NoneExposed: 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)
EPSS
46.4%
KEV
Not listed

Published

July 2, 2026

Last Modified

July 7, 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(1)

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.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 30× in last 7d / 30× 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. 2026-07-06 19:16 UTCEG score recompute
  2. 2026-07-06 19:16 UTCVendor advisory
  3. 2026-07-06 19:16 UTCGHSA enrichment
  4. 2026-07-06 16:27 UTCEPSS rescore
  5. 2026-07-06 16:27 UTCEPSS rescore
  6. 2026-07-06 06:15 UTCEG score recompute
  7. 2026-07-06 06:15 UTCVendor advisory
  8. 2026-07-06 06:15 UTCGHSA enrichment
  9. 2026-07-06 02:23 UTCEPSS rescore
  10. 2026-07-06 02:23 UTCEPSS rescore
  11. 2026-07-05 17:13 UTCEG score recompute
  12. 2026-07-05 17:13 UTCVendor advisory
  13. 2026-07-05 17:13 UTCGHSA enrichment
  14. 2026-07-05 04:12 UTCEG score recompute
  15. 2026-07-05 04:12 UTCVendor advisory
  16. 2026-07-05 04:12 UTCGHSA enrichment
  17. 2026-07-05 02:31 UTCEPSS rescore
  18. 2026-07-05 02:30 UTCEPSS rescore
  19. 2026-07-04 15:09 UTCEG score recompute
  20. 2026-07-04 15:09 UTCVendor advisory
  21. 2026-07-04 15:08 UTCGHSA enrichment
  22. 2026-07-04 02:08 UTCEG score recompute
  23. 2026-07-04 02:08 UTCVendor advisory
  24. 2026-07-04 02:08 UTCGHSA enrichment
  25. 2026-07-03 13:08 UTCEG score recompute
Show 5 more
  1. 2026-07-03 13:08 UTCVendor advisory
  2. 2026-07-03 13:07 UTCGHSA enrichment
  3. 2026-07-03 00:07 UTCEG score recompute
  4. 2026-07-03 00:07 UTCVendor advisory
  5. 2026-07-03 00:06 UTCNVD updatefirst tracked

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 7, 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 46.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-54998?
CVE-2026-54998 has a CVSS v3 base score of 8.8 (NVD).
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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