CVE-2026-101148 in BackupSheep Plugin
Summary
by MITRE • 10/01/2026
The BackupSheep WordPress Backup Plugin WordPress plugin through 1.8 does not properly validate its integration key, treating an unset or blank key as valid, which allows unauthenticated attackers to create and download full site backups, including the database with user password hashes, and to delete arbitrary files on the server, leading to sensitive data disclosure and site takeover.
The BackupSheep WordPress Backup Plugin WordPress plugin through 1.8 has been closed on WordPress.org since July 2024 and no fixed version is available. Remove it from any site where it is installed.
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Analysis
by VulDB Data Team • 10/01/2026
The vulnerability in the BackupSheep WordPress Backup Plugin, specifically affecting versions up to 1.8, represents a critical failure in authentication logic that fundamentally undermines the security posture of affected websites. The core technical flaw lies in the improper validation of integration keys used for administrative operations within the plugin's backup functionality. Instead of strictly requiring a valid, non-empty key to authorize actions such as creating backups or managing files, the application treats unset or blank values as legitimate credentials. This design oversight effectively bypasses authentication mechanisms, allowing any unauthenticated actor interacting with the plugin’s endpoints to execute privileged commands without providing proof of identity.
From an operational perspective, this flaw enables severe consequences including full site compromise and sensitive data exfiltration. Attackers can exploit this weakness to generate complete backups of the WordPress installation, which inherently includes the database containing user password hashes alongside configuration files and media assets. The exposure of these password hashes facilitates offline cracking attacks, potentially leading to credential reuse across other platforms if users employ weak or repeated passwords. Furthermore, the ability to delete arbitrary files on the server introduces a significant risk of denial-of-service conditions and can be leveraged as part of a broader attack chain to remove security logs, configuration files that restrict access, or core WordPress files, thereby destabilizing the application environment.
This vulnerability aligns with CWE-287, which describes Improper Authentication, where an actor is able to bypass authentication controls due to insufficient validation of credentials. Additionally, the ability to create backups and download them corresponds to ATT&CK technique T1005, Data from Local System, while the capability to delete arbitrary files maps to T1485, Data Destruction. The combination of these capabilities allows an attacker to perform reconnaissance by extracting sensitive data followed by impact actions that disrupt service integrity or destroy evidence.
Given that the plugin has been removed from the WordPress.org repository since July 2024 and no patched version exists, remediation requires immediate manual intervention rather than a simple software update. Site administrators must locate and completely uninstall the BackupSheep plugin from all affected installations to eliminate the attack surface entirely. It is also advisable to audit server logs for any signs of unauthorized backup downloads or file deletions that may have occurred prior to removal. Following deinstallation, rotating all user passwords on the site is strongly recommended to mitigate risks associated with previously exposed password hashes and to restore a secure authentication baseline.