CVE-2025-58879 is a vulnerability classified as 'Improper Control of Filename for Include/Require Statement in PHP Program,' commonly referred to as a Remote File Inclusion (RFI) vulnerability, found in the AncoraThemes Festy theme version 1.13.0 and earlier. The vulnerability arises because the PHP code in Festy improperly validates or sanitizes user-supplied input used in include or require statements. This flaw enables an attacker to supply a crafted filename parameter that points to a remote malicious PHP file, which the server then includes and executes. This leads to remote code execution capabilities, allowing attackers to run arbitrary code on the affected server. The CVSS v3.1 score of 8.2 reflects the vulnerability's network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), high confidentiality impact (C:H), low integrity impact (I:L), and no availability impact (A:N). The vulnerability affects websites using the Festy theme, which is popular in WordPress environments. Although no public exploits are currently known, the vulnerability's characteristics make it a critical risk for web servers hosting vulnerable versions of Festy. Attackers can leverage this flaw to steal sensitive data, implant backdoors, or pivot within the network. The lack of available patches at the time of publication necessitates immediate attention from administrators to implement temporary mitigations.

For European organizations, this vulnerability poses a significant threat to the confidentiality of sensitive information hosted on websites using the Festy theme. Successful exploitation can lead to unauthorized disclosure of customer data, intellectual property, and internal credentials. The partial integrity impact means attackers could modify some data or website content, potentially defacing sites or injecting malicious scripts for further attacks such as phishing or malware distribution. Although availability is not directly impacted, the presence of remote code execution can facilitate subsequent attacks that degrade service. Organizations in sectors such as e-commerce, finance, healthcare, and government are particularly at risk due to the sensitive nature of their data and regulatory requirements like GDPR. The vulnerability's remote and unauthenticated exploitability increases the attack surface, making it attractive for cybercriminals and advanced persistent threats targeting European digital infrastructure.

Immediate mitigation steps include disabling or removing the vulnerable Festy theme from production environments until a patch is released. Administrators should monitor official AncoraThemes channels for security updates and apply patches promptly once available. In the interim, restricting PHP include paths using configuration directives such as open_basedir can limit file inclusion to trusted directories. Implementing web application firewalls (WAFs) with rules to detect and block suspicious include/require parameters can reduce exploitation risk. Conduct thorough code reviews to identify and sanitize all user inputs used in file inclusion functions. Employing least privilege principles on web server accounts can limit the impact of successful exploitation. Regularly scanning web applications for vulnerabilities and anomalous behavior will aid in early detection. Finally, organizations should ensure robust backup and incident response plans are in place to recover from potential compromises.