CVE-2026-48579
Published: 04 June 2026
Summary
CVE-2026-48579 is a critical-severity Improper Authorization (CWE-285) vulnerability in Microsoft Exchange Online. Its CVSS base score is 9.1 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 41.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-34338
Vulnerability details
Improper authorization in Microsoft Exchange Online allows an unauthorized attacker to disclose information over a network.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Improper authorization in public-facing Exchange Online enables remote information disclosure, directly matching T1190.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Documented procedures facilitate correct implementation and ongoing management of authorization decisions.
Periodic reviews identify and correct flaws in authorization decisions or enforcement.
The control's documentation requirement reduces improper authorization by ensuring only mission-justified actions bypass authentication.
Establishing permitted attributes and values, plus auditing changes, ensures authorization decisions are based on correctly managed policy data.
Explicitly mandates authorizing remote access types before permitting connections, directly mitigating improper authorization.
The control explicitly requires authorization of each wireless access type prior to permitting connections.
Mandating explicit authorization of mobile device connections reduces the risk of improper authorization decisions for system access.
Specifying access authorizations for each account and requiring approvals for account requests enforces proper authorization decisions.