CVE-2026-48579: Microsoft Exchange Online Information Disclosure Vulnerability
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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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-48579
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Moderate exploitation riskCVE-2026-485791.0% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 61% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-48579 | coverage & exploitation status | NVD · CVE.org |
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