CVE-2025-4413 is a critical vulnerability affecting the Pixabay Images plugin for WordPress, developed by byrev. The flaw lies in the pixabay_upload function, which lacks proper file type validation, allowing authenticated users with Author-level privileges or higher to upload arbitrary files to the web server. This vulnerability is classified under CWE-434 (Unrestricted Upload of File with Dangerous Type). Because the plugin does not restrict or validate the file types being uploaded, attackers can potentially upload malicious files such as web shells or scripts that enable remote code execution (RCE). The vulnerability affects all versions of the plugin up to and including version 3.4. Exploitation requires no user interaction beyond the attacker having Author-level access, which is a relatively low privilege level in WordPress, often granted to contributors who can publish and manage their own posts. The CVSS v3.1 base score is 8.8 (high severity), reflecting the network attack vector, low attack complexity, and significant impact on confidentiality, integrity, and availability. Although no known exploits are currently reported in the wild, the vulnerability’s nature and ease of exploitation make it a high-risk issue. Successful exploitation could lead to full compromise of the affected WordPress site, including data theft, site defacement, or pivoting to internal networks. The vulnerability is particularly dangerous because WordPress is widely used, and plugins like Pixabay Images are popular for content management, increasing the attack surface. No official patches are currently available, so mitigation relies on access control and monitoring until a fix is released.

For European organizations using WordPress with the Pixabay Images plugin, this vulnerability poses a significant threat. Attackers with Author-level access—potentially obtained via credential compromise, phishing, or exploiting other vulnerabilities—can upload malicious files to the server, leading to remote code execution. This can result in data breaches, defacement, ransomware deployment, or use of the compromised server as a foothold for lateral movement within corporate networks. The impact extends to confidentiality (exposure of sensitive data), integrity (unauthorized content modification), and availability (site downtime or disruption). Organizations in sectors such as finance, healthcare, government, and media are particularly at risk due to the sensitive nature of their data and the reputational damage from website compromise. Additionally, the widespread use of WordPress in Europe means many SMEs and large enterprises could be affected. The lack of user interaction required and the relatively low privilege needed to exploit this vulnerability increase the likelihood of exploitation once an attacker gains Author-level access. This vulnerability could also be leveraged in targeted attacks against European entities, especially those with high-profile websites or critical online services.

1. Immediate mitigation should focus on restricting Author-level access to trusted users only, enforcing strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of account compromise. 2. Implement strict monitoring and logging of file upload activities and user actions within WordPress to detect anomalous behavior indicative of exploitation attempts. 3. Temporarily disable or remove the Pixabay Images plugin until an official patch is released by the vendor. 4. Employ web application firewalls (WAFs) with custom rules to block suspicious file uploads or execution of unauthorized scripts in upload directories. 5. Harden the WordPress environment by restricting execution permissions in upload directories and isolating the web server to limit the impact of potential RCE. 6. Conduct regular security audits and vulnerability scans focusing on plugin vulnerabilities and privilege escalation paths. 7. Educate site administrators and content authors about the risks of privilege misuse and encourage the principle of least privilege. 8. Once available, promptly apply vendor patches or updates addressing this vulnerability. 9. Consider implementing Content Security Policy (CSP) headers to mitigate the impact of malicious script execution.