CVE-2025-5396 in Bears Backup Plugin
Summary
by MITRE • 07/17/2025
The Bears Backup plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 2.0.0. This is due to the bbackup_ajax_handle() function not having a capability check, nor validating user supplied input passed directly to call_user_func(). This makes it possible for unauthenticated attackers to execute code on the server which can be leverage to inject backdoors or create new administrative user accounts to name a few things. On WordPress sites running the Alone theme versions 7.8.4 and older, this can be chained with CVE-2025-5394 to install the Bears Backup plugin and achieve the same impact.
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Analysis
by VulDB Data Team • 07/17/2025
The CVE-2025-5396 vulnerability represents a critical remote code execution flaw in the Bears Backup WordPress plugin, affecting all versions through 2.0.0. This vulnerability stems from inadequate security controls within the bbackup_ajax_handle() function which processes AJAX requests without proper authentication or authorization checks. The flaw creates a direct pathway for unauthenticated attackers to execute arbitrary code on affected WordPress installations, fundamentally compromising server integrity and security posture. The vulnerability's severity is amplified by the absence of input validation mechanisms that would normally prevent malicious data from being processed, allowing attackers to pass crafted parameters directly to the call_user_func() PHP function.
The technical exploitation of this vulnerability follows a well-established pattern of privilege escalation through insecure function calls. The bbackup_ajax_handle() function lacks capability checks that would normally verify user permissions before executing sensitive operations, creating an authentication bypass scenario. When malicious input is passed to call_user_func(), the PHP function executes the provided string as a function call, enabling attackers to invoke arbitrary PHP functions on the server. This primitive execution mechanism provides attackers with complete control over the affected system, allowing them to execute shell commands, manipulate files, and establish persistent access. The vulnerability aligns with CWE-863, which addresses "Incorrect Authorization" issues where security checks are not properly enforced, and represents a classic example of insufficient input validation that enables code injection attacks.
The operational impact of this vulnerability extends beyond simple code execution to encompass full system compromise and potential data exfiltration. Attackers can leverage this vulnerability to install backdoors, create administrative user accounts, and establish persistent access to compromised WordPress installations. The vulnerability's exploitation potential is particularly concerning when combined with other security flaws, as demonstrated by the chaining opportunity with CVE-2025-5394 in Alone theme environments. This combination allows attackers to first install the vulnerable Bears Backup plugin through the chained vulnerability, then immediately exploit the RCE flaw to gain complete administrative control. The attack vector represents a significant threat to WordPress site owners, as it requires no authentication credentials and can be exploited through automated scanning tools, making it a prime target for mass exploitation campaigns.
The exploitation chain involving CVE-2025-5396 and CVE-2025-5394 demonstrates how multiple vulnerabilities can be combined to create more severe security impacts than individual flaws alone. When attackers can first gain access to install malicious plugins through one vulnerability, they can then immediately leverage the RCE capability of Bears Backup to establish persistent access. This scenario aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: PowerShell" and T1566.001 for "Phishing: Spearphishing Attachment" in cases where attackers use automated tools to discover and exploit these vulnerabilities. Organizations running WordPress sites with the Alone theme version 7.8.4 or earlier are particularly vulnerable as they face a complete attack chain that begins with plugin installation and ends with full system compromise. The vulnerability affects not just individual sites but can potentially be used to create botnet infrastructure or serve as a stepping stone for broader network attacks against connected systems.
Mitigation strategies for CVE-2025-5396 must include immediate plugin updates to versions that address the authentication and input validation flaws, along with comprehensive monitoring for suspicious activity. Security teams should implement network-based detection measures to identify exploitation attempts, including monitoring for unusual AJAX requests and function calls that could indicate exploitation. The vulnerability's presence in the Alone theme environment highlights the importance of keeping all WordPress components updated, including themes, plugins, and core WordPress installations. Organizations should also consider implementing web application firewalls to detect and block malicious requests targeting the vulnerable bbackup_ajax_handle() function. Additionally, regular security audits and vulnerability assessments should be conducted to identify other potential attack vectors that could be exploited in similar ways. The remediation process should include immediate patching of the Bears Backup plugin, verification of system integrity, and implementation of proper access controls to prevent unauthorized installations of malicious plugins.