CVE-2026-69943 in SharePoint Server
Summary
by MITRE • 10/14/2026
Improper limitation of a pathname to a restricted directory ('path traversal') in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described constitutes a critical path traversal flaw within the Microsoft Office SharePoint server infrastructure, specifically categorized under CWE-22: Improper Limitation of a Pathname to a Restricted Directory. This class of vulnerabilities arises when software constructs file paths or URLs using user-supplied input without adequately validating that the resulting path remains confined within an intended secure directory structure. In this specific instance, the flaw allows for remote code execution by enabling an attacker to manipulate file system references through carefully crafted requests. Although the vulnerability requires authentication and thus involves an authorized attacker, the ability to traverse outside of restricted directories represents a severe compromise of application logic integrity. The technical mechanism typically involves injecting sequence characters such as dot-dot-slash (../) or their URL-encoded variants into input fields that are subsequently used in file system operations like reading configuration files, loading templates, or accessing static assets. By manipulating these paths, the attacker can bypass access controls designed to isolate specific application components from sensitive areas of the server's operating system.
From an operational perspective, this vulnerability poses a significant risk because it facilitates remote code execution on systems that are often central to enterprise document management and collaboration workflows. SharePoint servers frequently handle highly confidential data and serve as gateways for internal network resources. An attacker who successfully exploits this path traversal flaw can potentially read arbitrary files from the server's file system, including configuration files containing database credentials or encryption keys. More critically, if the application allows writing operations to specific directories that are later interpreted by a web engine or script interpreter, the attacker may upload malicious scripts or binaries and trigger their execution through subsequent requests. This transforms what might initially appear as an information disclosure issue into a full system compromise, allowing the attacker to establish persistence, escalate privileges, and pivot further into the internal network. The requirement for authentication does not mitigate the severity of remote code execution; rather, it highlights that insider threats or compromised credentials can lead to catastrophic outcomes due to insufficient input validation on server-side path construction logic.
The exploitation of this vulnerability aligns with several techniques documented in the MITRE ATT&CK framework, particularly those related to Initial Access and Execution via Web Shell deployment. Attackers may leverage this flaw as part of a broader attack chain where they first gain valid credentials through phishing or credential stuffing, then exploit the path traversal to upload a web shell into a writable directory with execute permissions. Once executed, the web shell provides an interactive command-line interface on the server, effectively granting the attacker control over the underlying operating system environment. This behavior is consistent with techniques such as T1505.002: Web Shell and potentially T1083: File and Directory Discovery if the primary goal is reconnaissance before escalation. The presence of this vulnerability indicates a failure in implementing secure coding practices, specifically the lack of canonicalization checks or strict allow-listing of permitted directory paths during request processing.
To mitigate this risk, immediate remediation should focus on applying vendor-provided security patches that address the underlying input validation logic within SharePoint components responsible for handling file path inputs. Administrators must ensure that all updates are applied promptly to close the window of exposure. In addition to patching, defense-in-depth strategies should be employed, including restricting write permissions on web server directories to only those absolutely necessary for application functionality and ensuring that executable scripts cannot reside in upload or temporary directories where user input is processed. Network segmentation can also limit the blast radius by isolating SharePoint servers from critical database backends and other sensitive internal systems. Furthermore, implementing strict output encoding and validating all file path inputs against a whitelist of allowed characters and directory structures will prevent traversal sequences from being interpreted as valid navigation commands. Regular security audits focusing on input validation patterns across web applications are essential to identify similar flaws before they can be exploited by adversaries seeking to gain unauthorized access to enterprise environments.