CVE-2025-8289 is a deserialization vulnerability classified under CWE-502 found in the themeisle Redirection for Contact Form 7 plugin for WordPress, affecting all versions up to 3.2.4. The vulnerability arises from unsafe deserialization of untrusted input in the delete_associated_files function, allowing unauthenticated attackers to inject malicious PHP objects. Exploitation requires the presence of a form with a file upload action on the site and the activation of the 'Redirection For Contact Form 7 Extension - Create Post' extension. The vulnerability does not affect sites running PHP versions above 8 due to changes in PHP object handling. Crucially, no proof-of-concept (POP) chain exists within the vulnerable plugin itself, so exploitation depends on the presence of another plugin or theme that provides a POP chain, enabling the attacker to perform actions such as arbitrary file deletion, sensitive data retrieval, or code execution. Contact Form 7 itself contains a gadget that can facilitate arbitrary file deletion when combined with this vulnerability and the extension, making sites with both plugins and the extension enabled particularly at risk. The CVSS v3.1 score is 7.5, indicating high severity, with attack vector network, high attack complexity, no privileges required, user interaction required, and high impact on confidentiality, integrity, and availability. No patches are currently linked, and no exploits are known in the wild as of the publication date.

The vulnerability enables unauthenticated remote attackers to inject malicious PHP objects via deserialization, potentially leading to arbitrary file deletion, data leakage, or remote code execution depending on the presence of a POP chain in other installed plugins or themes. This can result in complete compromise of affected WordPress sites, including defacement, data loss, or use of the site as a pivot point for further attacks. The requirement for the 'Redirection For Contact Form 7 Extension - Create Post' extension and a file upload form narrows the attack surface but still affects a significant subset of WordPress sites using these plugins. The impact extends to confidentiality (data exposure), integrity (file deletion or modification), and availability (site disruption). Given WordPress's widespread use, this vulnerability poses a substantial risk to websites globally, especially those with outdated PHP versions (<=8) and the specified plugin ecosystem.

1. Immediately update or disable the themeisle Redirection for Contact Form 7 plugin if an update addressing this vulnerability becomes available. 2. If no patch is available, disable or uninstall the 'Redirection For Contact Form 7 Extension - Create Post' extension to prevent exploitation. 3. Upgrade PHP to version 8 or higher, as the vulnerability does not affect PHP versions above 8. 4. Audit all installed plugins and themes for the presence of POP chains that could be leveraged in conjunction with this vulnerability, and remove or update vulnerable components. 5. Restrict file upload forms or implement strict validation and sanitization to reduce attack vectors. 6. Employ Web Application Firewalls (WAFs) with rules targeting deserialization attacks and monitor logs for suspicious activity related to the vulnerable functions. 7. Regularly back up website data and files to enable recovery in case of compromise. 8. Conduct security assessments focusing on plugin dependencies and interactions to identify chained vulnerabilities.