CVE-2026-48579
Improper authorization in Microsoft Exchange Online allows an unauthorized attacker to disclose information over a network.
CSIRTS triage
- What
- Improper authorization allows unauthorized information disclosure over a network.
- Who is affected
- Users of Microsoft Exchange Online.
- Urgency
- Critical urgency due to the potential for information disclosure with a CVSS score of 9.1.
- Action
- Implement recommended security measures and monitor for unauthorized access.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Moderate exploitation risk1.0% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 59% of all EPSS-scored CVEs.
Advisory coverage (1)
- criticalCVE-2026-48579: Microsoft Exchange Online Information Disclosure Vulnerabilitymsrc · 2026-06-09
External references
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[](https://www.csirts.com/cve/CVE-2026-48579)