CVE-2026-54998: CWE-863: Incorrect Authorization in Microsoft Microsoft Exchange Online
Incorrect authorization in Microsoft Exchange Online allows an authorized attacker to elevate privileges over a network.
AI Analysis
Technical Summary
This vulnerability (CVE-2026-54998) in Microsoft Exchange Online is classified as CWE-863 (Incorrect Authorization). It enables an attacker who already has some level of authorization to escalate their privileges remotely over the network. The CVSS 3.1 base score is 8.8, indicating high severity with network attack vector, low attack complexity, and no user interaction required. The vulnerability impacts confidentiality, integrity, and availability. Microsoft has published an official fix to address this issue.
Potential Impact
An authorized attacker can exploit this vulnerability to elevate privileges within Microsoft Exchange Online, potentially gaining unauthorized access to sensitive information and performing privileged actions that compromise system confidentiality, integrity, and availability.
Mitigation Recommendations
An official fix is available from Microsoft. Users and administrators should apply the patch provided in the Microsoft security update advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54998 to remediate this vulnerability.
CVE-2026-54998: CWE-863: Incorrect Authorization in Microsoft Microsoft Exchange Online
Description
Incorrect authorization in Microsoft Exchange Online allows an authorized attacker to elevate privileges over a network.
CVSS v3.1
Score 8.8high
Affected software
Microsoft
Microsoft Exchange Online
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-54998) in Microsoft Exchange Online is classified as CWE-863 (Incorrect Authorization). It enables an attacker who already has some level of authorization to escalate their privileges remotely over the network. The CVSS 3.1 base score is 8.8, indicating high severity with network attack vector, low attack complexity, and no user interaction required. The vulnerability impacts confidentiality, integrity, and availability. Microsoft has published an official fix to address this issue.
Potential Impact
An authorized attacker can exploit this vulnerability to elevate privileges within Microsoft Exchange Online, potentially gaining unauthorized access to sensitive information and performing privileged actions that compromise system confidentiality, integrity, and availability.
Mitigation Recommendations
An official fix is available from Microsoft. Users and administrators should apply the patch provided in the Microsoft security update advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54998 to remediate this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-06-16T14:10:05.869Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54998","vendor":"Microsoft"}]
Threat ID: 6a46e7f427e9c797193afcb7
Added to database: 07/02/2026, 22:36:36 UTC
Last enriched: 08/17/2026, 14:04:57 UTC
Last updated: 10/01/2026, 01:41:34 UTC
Views: 205
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