CVE-2026-15021 in wpForo Forum Plugin
Summary
by MITRE • 07/16/2026
The wpForo Forum plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'location' Profile Field in all versions up to, and including, 3.1.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The sanitize_text_field() function applied at input does not encode double quotes, allowing attribute breakout via a payload that escapes the href attribute context and injects event handler attributes.
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Analysis
by VulDB Data Team • 07/16/2026
The wpForo Forum plugin for WordPress presents a critical stored cross-site scripting vulnerability that affects all versions up to and including 3.1.1, representing a significant security risk for WordPress installations. This vulnerability resides within the profile field handling mechanism, specifically targeting the 'location' profile field where users can input textual information. The flaw stems from inadequate input sanitization processes that fail to properly escape or encode user-supplied data before storage and subsequent output rendering.
The technical implementation of this vulnerability exploits the insufficient application of the sanitize_text_field() function during input processing. While this function provides basic text sanitization, it fails to adequately handle double quotes which are essential for breaking out of HTML attribute contexts. Attackers with subscriber-level privileges or higher can leverage this weakness by crafting malicious payloads that exploit attribute breakout techniques within the href attribute context, effectively injecting event handler attributes into the profile field data. This allows them to bypass standard output escaping mechanisms that would normally prevent script execution.
The operational impact of this vulnerability extends beyond simple data corruption or display issues, as it enables persistent malicious code injection that can affect all users who view affected pages. When authenticated users access pages containing the injected scripts, the malicious code executes in their browsers with the privileges of the victim user, potentially leading to session hijacking, credential theft, or further privilege escalation attacks. The stored nature of this vulnerability means that once injected, the malicious payloads persist indefinitely until manually removed by administrators, creating a long-term security risk for affected installations.
This vulnerability aligns with CWE-79, which describes Cross-Site Scripting flaws in web applications where input data is not properly sanitized before being rendered to users. The specific exploitation technique demonstrates elements of ATT&CK tactic TA0001 (Initial Access) and TA0002 (Execution) through the use of authenticated user accounts to establish persistent malicious presence within the application environment. Organizations running affected versions of wpForo should immediately implement mitigations such as upgrading to patched versions, implementing additional input validation layers, or applying custom filters that properly escape all HTML attribute contexts including double quotes and other potentially dangerous characters.
The root cause analysis reveals that the plugin's security model fails to account for attribute breakout scenarios during input sanitization, particularly when dealing with HTML attributes that accept dynamic values. This oversight creates a dangerous gap in the application's defense-in-depth strategy where basic sanitization functions are insufficient against sophisticated injection techniques. The vulnerability demonstrates how even seemingly benign input fields can become attack vectors when proper escaping and encoding mechanisms are not consistently applied across all output contexts, highlighting the critical importance of comprehensive security testing that includes attribute-level validation rather than relying solely on generic text sanitization approaches.