CVE-2026-88137 in Windows
Summary
by MITRE • 10/14/2026
Files or directories accessible to external parties in WebDAV allows an authorized attacker to disclose information over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described involves the improper restriction of access controls within a Web Distributed Authoring and Versioning (WebDAV) server implementation, leading to unauthorized disclosure of sensitive files or directories. This flaw typically arises when the server fails to properly validate user permissions against specific resource paths before granting read access. In many enterprise environments, WebDAV is enabled for remote file management and collaboration purposes. However, if the configuration does not strictly enforce authentication and authorization checks on all endpoints, an attacker who possesses valid credentials can exploit this misconfiguration to traverse directories or access files that were intended to be restricted to internal users only. This scenario represents a classic case of broken access control where the system trusts user input regarding resource location without sufficient verification against security policies.
From a technical perspective, this issue aligns with CWE-284 Improper Access Control and often falls under CWE-538 Insertion of Sensitive Information into Externally-Accessible File or Directory if the exposure results in sensitive data being written to publicly accessible locations due to flawed logic. The operational impact is significant as it allows an authenticated attacker to exfiltrate confidential information such as internal documents, configuration files containing credentials, source code, or personal identifiable information over a network connection. Since WebDAV operates primarily over HTTP and HTTPS ports like 80 and 443, this traffic often blends with legitimate web activity, making detection by standard perimeter security devices difficult without deep packet inspection or specific behavioral analysis rules. The attacker does not need to exploit a software bug in the traditional sense but rather leverages insufficiently configured access controls to bypass intended restrictions.
This vulnerability maps directly to the MITRE ATT&CK technique T1083 File and Directory Discovery, where adversaries use legitimate system utilities or protocols to gather information about the target environment. By accessing restricted directories through WebDAV, an attacker can map out the network structure, identify high-value targets for further exploitation, and potentially escalate privileges if sensitive configuration files reveal internal IP addresses, service accounts, or other critical infrastructure details. The ability to read these resources facilitates subsequent phases of a cyber attack lifecycle including credential harvesting and lateral movement preparation.
Mitigation strategies should focus on strict adherence to the principle of least privilege regarding WebDAV configurations. Administrators must ensure that only necessary directories are exposed via WebDAV and that all other paths return appropriate access denied errors rather than listing contents or allowing downloads. It is critical to implement robust authentication mechanisms such as multi-factor authentication for any service exposing file systems remotely. Additionally, network segmentation should be employed so that WebDAV services are not directly accessible from untrusted networks like the public internet unless absolutely necessary and protected by a web application firewall with specific rulesets designed to detect anomalous directory traversal or excessive read operations. Regular auditing of access logs is also recommended to identify any unauthorized attempts to access restricted resources, ensuring timely detection and response to potential breaches.