CVE-2025-26957 is a Local File Inclusion (LFI) vulnerability found in the Deetronix Affiliate Coupons plugin for PHP-based applications, specifically affecting versions up to and including 1.7.3. The vulnerability arises from improper control over the filename parameter used in PHP's include or require statements, which allows an attacker to manipulate the input to include arbitrary files from the local server filesystem. This can lead to unauthorized disclosure of sensitive files such as configuration files, source code, or credentials stored on the server. In some cases, LFI can be leveraged to execute arbitrary code if combined with other vulnerabilities or if the attacker can upload malicious files. The vulnerability is classified as a PHP Remote File Inclusion type but is actually a Local File Inclusion issue, meaning the attacker cannot directly include remote files but can access local files. The plugin's failure to properly sanitize or validate the filename input parameter is the root cause. Although no public exploits are currently known, the vulnerability is publicly disclosed and thus could be targeted by attackers. The absence of a CVSS score indicates that the severity has not been formally assessed, but the technical details suggest a significant risk. The vulnerability affects a widely used plugin in affiliate marketing contexts, which often run on WordPress or similar PHP platforms, increasing the potential attack surface. The issue was reserved and published in February 2025 by Patchstack, indicating recent discovery and disclosure.

The impact of CVE-2025-26957 can be substantial for organizations using the affected Deetronix Affiliate Coupons plugin. Successful exploitation can lead to unauthorized access to sensitive server files, including configuration files, database credentials, and application source code, compromising confidentiality. Attackers may use this information to escalate privileges, conduct further attacks, or pivot within the network. In some scenarios, LFI vulnerabilities can be chained with other exploits to achieve remote code execution, severely impacting system integrity and availability. For e-commerce and affiliate marketing platforms, this can result in data breaches, loss of customer trust, financial losses, and regulatory penalties. The vulnerability does not require authentication, increasing the risk of exploitation by remote attackers. Given the plugin’s usage in affiliate coupon management, attackers might also manipulate coupon data or affiliate tracking, affecting business operations and revenue. The lack of known exploits in the wild currently limits immediate widespread impact, but the public disclosure increases the likelihood of future attacks. Organizations worldwide that rely on PHP-based affiliate marketing plugins are at risk, especially those that have not applied updates or mitigations.

To mitigate CVE-2025-26957, organizations should immediately update the Deetronix Affiliate Coupons plugin to a patched version once available. In the absence of an official patch, implement strict input validation and sanitization on all parameters used in include or require statements to ensure only intended files can be included. Employ whitelisting of allowable filenames or paths to prevent arbitrary file inclusion. Disable the ability to include remote files by setting 'allow_url_include' to 'Off' in the PHP configuration. Restrict file permissions on the server to limit access to sensitive files and directories. Monitor web server logs and application logs for suspicious requests attempting to manipulate include parameters. Use Web Application Firewalls (WAFs) to detect and block exploitation attempts targeting LFI vulnerabilities. Conduct regular security audits and code reviews of PHP applications and plugins to identify similar issues proactively. Educate development teams on secure coding practices related to file inclusion and input handling. Finally, maintain an incident response plan to quickly address any exploitation attempts.