CVE-2026-28092 in Sounder Plugin
Summary
by MITRE • 03/05/2026
Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion') vulnerability in ThemeREX Sounder sounder allows PHP Local File Inclusion.This issue affects Sounder: from n/a through <= 1.3.11.
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Analysis
by VulDB Data Team • 03/07/2026
The vulnerability identified as CVE-2026-28092 represents a critical PHP Remote File Inclusion flaw within the ThemeREX Sounder theme, specifically affecting versions through 1.3.11. This vulnerability resides in the improper control of filename parameters within include/require statements, creating a pathway for attackers to execute arbitrary code through manipulation of file inclusion directives. The flaw stems from insufficient validation and sanitization of user-supplied input that is directly used in PHP's include or require functions, allowing malicious actors to specify arbitrary file paths that can be executed within the context of the web application.
The technical implementation of this vulnerability exploits the fundamental PHP functionality where include or require statements can accept dynamic parameters. When user input is directly concatenated into these statements without proper validation, attackers can inject malicious file paths that point to remote servers or local files containing malicious code. This creates a dangerous condition where legitimate PHP execution flows can be hijacked to load and execute attacker-controlled content, effectively bypassing normal security boundaries. The vulnerability specifically impacts the Sounder theme's file inclusion mechanisms, where parameters controlling which files are included are not properly validated against a whitelist of acceptable values.
From an operational perspective, this vulnerability presents a severe risk to affected systems as it allows for arbitrary code execution, which can lead to complete system compromise. Attackers can leverage this flaw to upload backdoors, escalate privileges, steal sensitive data, or establish persistent access to the compromised environment. The impact extends beyond immediate code execution as it can enable further exploitation through lateral movement within the network, potentially affecting other systems that share the same infrastructure. The vulnerability's exploitation requires minimal prerequisites since it targets the core PHP functionality that is commonly used in web applications, making it particularly dangerous in environments where multiple applications might be running on the same server.
Security mitigations for this vulnerability should focus on implementing strict input validation and sanitization practices for all user-supplied parameters that are used in file inclusion contexts. The recommended approach includes implementing a whitelist-based validation system where only predetermined, safe file paths are allowed for inclusion, rather than accepting arbitrary user input. Additionally, disabling remote file inclusion in PHP configuration through setting allow_url_include to off provides an additional layer of protection. The implementation of proper parameter validation and the use of absolute paths for file inclusion operations can significantly reduce the attack surface. Organizations should also consider implementing web application firewalls that can detect and block suspicious file inclusion patterns, and conduct regular security audits to identify similar vulnerabilities in other components of the application stack. This vulnerability aligns with CWE-98 and CWE-89 categories, representing improper input validation and code injection respectively, and maps to ATT&CK technique T1505.003 for remote service injection and T1059.007 for scripting.