CVE-2026-70246 in SharePoint
Summary
by MITRE • 10/14/2026
Incorrect authorization in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described represents a critical flaw within the access control mechanisms of Microsoft Office SharePoint, specifically categorized under CWE-269: Improper Privilege Management. This type of defect occurs when the application fails to properly enforce restrictions on what authorized users can do or what actions they are permitted to execute via an API. In this specific instance, the architectural design allows a user who possesses valid authentication credentials and basic access rights to manipulate internal logic flows in a manner that bypasses intended security boundaries. The core technical flaw lies not in the initial authentication process but in the subsequent authorization checks performed by the server-side components when processing requests related to administrative or elevated functions. An attacker with legitimate, albeit limited, network access can craft specific HTTP requests that exploit these insufficiently validated parameters, tricking the SharePoint service into executing privileged operations as if they were initiated by a system administrator or higher-privileged account.
From an operational perspective, this vulnerability enables privilege escalation over a network without requiring physical access to the server or complex local exploitation techniques. Once an attacker successfully elevates their privileges, they gain control equivalent to that of a SharePoint farm administrator. This level of access is particularly dangerous because it grants unrestricted read and write capabilities across all site collections within the environment. The attacker can extract sensitive corporate data, modify configuration settings, inject malicious scripts into web parts, or install backdoors for persistent access. Furthermore, since SharePoint often integrates with other enterprise systems such as Active Directory and SQL Server, compromising these elevated privileges can serve as a pivot point for lateral movement across the broader network infrastructure. This significantly expands the blast radius of the initial breach, potentially leading to full domain compromise if not contained promptly.
The exploitation vector aligns closely with MITRE ATT&CK technique T1078: Valid Accounts, where adversaries use legitimate credentials to gain access, combined with aspects of T1548: Abuse Elevation Control Mechanism, as the attacker abuses system mechanisms to increase their privilege level. The lack of strict role-based access control validation in specific API endpoints or administrative interfaces allows this abuse to occur seamlessly over standard network protocols like HTTP and HTTPS. This makes detection challenging for traditional perimeter security tools that may not inspect the semantic content of authenticated web traffic deeply enough to identify logic-based abuses versus simple injection attacks.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary defense is applying the latest cumulative updates or security patches released by Microsoft, which typically include fixes for these authorization logic flaws in SharePoint Server components. Organizations should also implement strict network segmentation to limit lateral movement opportunities between web-facing servers and internal database or application tiers. Additionally, enforcing multi-factor authentication adds a layer of complexity that can hinder attackers even if they obtain valid credentials through other means such as phishing. From an architectural standpoint, adopting the principle of least privilege ensures that service accounts and user profiles are granted only the minimum permissions necessary for their function. Regular auditing of administrative actions and monitoring for anomalous behavior patterns in SharePoint logs can also help detect exploitation attempts early before significant damage occurs.