CVE-2026-47655 in Graph
Summary
by MITRE • 06/05/2026
Exposure of sensitive information to an unauthorized actor in Microsoft Graph allows an authorized attacker to disclose information over a network.
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Analysis
by VulDB Data Team • 06/05/2026
This vulnerability represents a critical information disclosure flaw within Microsoft Graph API that enables authenticated attackers to access sensitive data through network communications. The issue stems from inadequate access controls and authorization mechanisms within the Microsoft Graph service, allowing malicious actors who have already established some level of authentication to escalate their privileges and extract confidential information. The vulnerability operates at the application layer and can be exploited over network connections, making it particularly dangerous in cloud environments where Microsoft Graph serves as a central hub for accessing Microsoft 365 services and data. From a cybersecurity perspective, this represents a classic privilege escalation scenario where initial access is leveraged to gain broader data access capabilities, potentially exposing user credentials, organizational data, and sensitive business information.
The technical implementation of this vulnerability typically involves improper validation of access tokens and insufficient scope checking within Microsoft Graph API endpoints. Attackers can exploit this by crafting malicious requests that bypass normal authorization checks, potentially accessing data from other users or systems they shouldn't have access to. This flaw often manifests as a lack of proper resource-based access control or inadequate session management, allowing attackers to traverse access boundaries that should normally be enforced. The vulnerability can be categorized under CWE-284 Access Control Issues, specifically related to insufficient access control mechanisms and improper privilege management within cloud service APIs. This aligns with ATT&CK technique T1078 Valid Accounts, where adversaries leverage legitimate credentials to access resources beyond their intended scope, and T1566 Phishing, as initial access might be gained through social engineering to obtain valid credentials before exploiting this information disclosure vulnerability.
The operational impact of this vulnerability extends beyond immediate data exposure to encompass long-term security implications for affected organizations. Organizations using Microsoft Graph for unified access to Microsoft 365 services face potential breaches of sensitive corporate data including emails, documents, calendar information, and user profiles. The attack surface is particularly broad since Microsoft Graph integrates with numerous Microsoft services including Exchange Online, SharePoint Online, and Azure Active Directory, meaning a single vulnerability can potentially expose data across multiple systems. This vulnerability is especially concerning in environments where organizations rely heavily on Microsoft 365 for business operations, as it can lead to significant financial losses, regulatory compliance violations, and reputational damage. The network-based nature of the exploit means that attackers can potentially access sensitive information from remote locations without requiring physical access to the organization's infrastructure, making detection and prevention more challenging.
Organizations should implement multiple layers of defense to mitigate this vulnerability including regular security assessments of Microsoft Graph API usage, implementation of principle of least privilege access controls, and continuous monitoring of API access patterns for anomalous behavior. Configuration management should ensure that access tokens and API keys are properly rotated and that applications only request the minimum necessary permissions. Security teams should leverage Microsoft Defender for Cloud Apps and similar monitoring solutions to detect unusual API access patterns that might indicate exploitation attempts. Additionally, organizations should regularly review and update their Microsoft 365 application permissions, implement multi-factor authentication for administrative accounts, and maintain detailed audit logs of all API access activities. The vulnerability highlights the importance of comprehensive API security practices and the need for organizations to treat cloud service APIs as critical attack surfaces requiring continuous security attention and monitoring.