CVE-2026-48582 — Microsoft Exchange Online - Missing Authorization Leading to Privilege Escalation
Missing authorization in Microsoft Exchange Online allows an authorized attacker to elevate privileges over a network.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.7% (30-day exploitation probability)+8
- Technical severity (critical)+10
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Microsoft Exchange Online).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Microsoft | Exchange Online | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Microsoft | Exchange Online | version - | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 9.6 | CVSS 3.1 | Critical | 3.1 | 5.8 | secure@microsoft.com via NIST National Vulnerability Database |
| 9.6 | CVSS 3.1 | Critical | — | — | microsoft via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N (score shown at the top: secure@microsoft.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.69%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Audit administrative actions and access to resources outside each user’s normal pattern.
Analysis and videos
CVE-2026-48582: Microsoft Exchange Online - Missing Authorization Leading to Privilege Escalation
Microsoft has published CVE-2026-48582, a missing authorization flaw (CWE-862) in Microsoft Exchange Online that lets an authorized attacker elevate privileges over the network. The CNA rates it critical with a CVSS 3.1 base score of 9.6. The sources consulted list no confirmed exploitation and no affected or fixed version numbers.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · microsoft/microsoft exchange online
- SSVC assessment updated
- Record published
- CVSS changed · 9.6
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
1 on the record
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-65801 Microsoft Exchange Online Elevation of Privilege Vulnerability Aug 20, 2026
- Critical CVE-2026-56191 Microsoft Exchange Online Tampering Vulnerability Jul 23, 2026
- High CVE-2026-54998 Microsoft Exchange Online Elevation of Privilege Vulnerability Jul 2, 2026
- High CVE-2026-48579 Microsoft Exchange Online Information Disclosure Vulnerability Jun 4, 2026
- Critical CVE-2026-26137 Microsoft Exchange Elevation of Privilege Vulnerability Mar 19, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-48582 is "Microsoft Exchange Online - Missing Authorization Leading to Privilege Escalation", rated Critical. It affects Exchange Online (Microsoft); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.6 describes technical severity. EPSS 0.69% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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