CVE-2026-86815 in BackWPup Plugin
Summary
by MITRE • 09/11/2026
The BackWPup WordPress plugin before 5.7.5 does not properly restrict access to several of its REST API routes for job, backup-destination, and backup-execution management, allowing users holding a BackWPup WordPress plugin before 5.7.5-defined, administrator-assigned limited role to create and run backup jobs and exfiltrate a full database backup to an attacker-controlled destination.
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Analysis
by VulDB Data Team • 09/11/2026
The vulnerability identified in the BackWPup WordPress plugin prior to version 5.7.5 represents a critical failure in access control mechanisms within the application's REST API implementation. This flaw specifically affects routes responsible for managing backup jobs, configuring backup destinations, and executing backups. The core technical issue stems from insufficient authorization checks that fail to properly validate whether the authenticated user possesses the necessary privileges to perform administrative actions on these specific endpoints. While the plugin defines limited roles intended to restrict certain capabilities, the underlying code does not enforce these restrictions at the API level for job creation, destination configuration, and execution triggers. This discrepancy allows users assigned with restricted administrator-assigned roles to bypass expected limitations and interact with sensitive backend functions as if they had full administrative privileges.
From a technical perspective, this vulnerability is classified under CWE-269, which denotes Improper Privilege Control. The absence of robust server-side validation means that the application relies on client-side restrictions or incomplete role checks rather than enforcing strict access policies based on user permissions. When an attacker exploits this flaw, they can utilize standard HTTP requests to invoke these REST API endpoints without triggering appropriate denial responses. This allows them to initiate backup processes and define external storage locations for the resulting data archives. The exploitation does not require complex injection techniques or buffer overflows but rather a straightforward abuse of poorly secured administrative interfaces exposed through the WordPress REST API framework, which is commonly accessible via standard web requests if authentication cookies are present.
The operational impact of this vulnerability is severe due to its potential for significant data exfiltration and system compromise. An attacker with limited access can create new backup jobs that target the entire WordPress database or specific sensitive tables containing user credentials, personal identifiable information, and proprietary content. By configuring a backup destination pointing to an attacker-controlled server via protocols such as FTP, SFTP, or Amazon S3, the adversary can retrieve complete copies of the site's data. This leads directly to CWE-200, which covers Information Exposure, resulting in the loss of confidentiality for stored user data and potentially sensitive business information. Furthermore, if the backup includes configuration files containing database credentials or API keys, it may facilitate further lateral movement within the hosting environment or compromise other systems that share those credentials.
In terms of threat modeling, this vulnerability aligns with MITRE ATT&CK techniques related to Collection via Remote Access Tools and Data Exfiltration over Non-Encrypted Channels if the destination is not secured properly. The attacker effectively uses the legitimate backup functionality as a vector for data theft, making detection more difficult since the activity appears consistent with normal administrative operations. This abuse of trusted application features highlights the importance of validating every action against strict permission sets rather than assuming that limited roles inherently prevent access to all sensitive modules.
To mitigate this risk, organizations running BackWPup versions earlier than 5.7.5 must upgrade immediately to the patched version where these REST API routes have been secured with proper capability checks. Until an update is applied, administrators should consider restricting access to the WordPress admin area through IP whitelisting or two-factor authentication to reduce the attack surface. Additionally, reviewing user roles and ensuring that no users are assigned overly broad permissions unnecessarily can limit the potential impact if a similar vulnerability exists elsewhere in the plugin ecosystem. Regular audits of API endpoint security and adherence to principle of least privilege are essential practices for maintaining the integrity of WordPress-based applications against such access control bypasses.