What is CVE-2026-48579?

CVE-2026-48579 is a critical-severity vulnerability in Microsoft Exchange_online, classified under Improper Authorization. CVSS score: 9.1/10. Published 2026-06-04.

How severe is CVE-2026-48579?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Auth bypass in Microsoft Exchange_online

CVE-2026-48579

Improper authorization in Microsoft Exchange Online allows an unauthorized attacker to disclose information over a network.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

Affected products

Microsoft Exchange_online
Microsoft Exchange Online

Weakness classification (CWE)

CWE-285 — Improper Authorization

References

secure@microsoft.com (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-48579?: CVE-2026-48579 is a critical-severity vulnerability in Microsoft Exchange_online, classified under Improper Authorization. CVSS score: 9.1/10. Published 2026-06-04.
How severe is CVE-2026-48579?: Critical severity. CVSS v3 base score is 9.1 out of 10.