CVE-2026-54868 in FV Simpler SEO Plugin
Summary
by MITRE • 10/13/2026
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in FolioVision FV Simpler SEO fv-all-in-one-seo-pack allows Stored XSS.This issue affects FV Simpler SEO: from n/a through 1.9.7.
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Analysis
by VulDB Data Team • 10/13/2026
The identified vulnerability represents a classic instance of Improper Neutralization of Input During Web Page Generation, commonly known as Cross-Site Scripting or XSS. Specifically, this flaw manifests as a Stored XSS within the FolioVision FV Simpler SEO plugin for WordPress, affecting versions ranging from n/a through 1.9.7. In web application security taxonomy, stored XSS is considered particularly severe because the malicious payload is permanently saved on the target server, typically in a database or content management system field, rather than being transiently passed via URL parameters as seen in reflected XSS attacks. This persistence ensures that every user who views the affected page will execute the injected script without any additional interaction required from them beyond loading the compromised page.
The technical root cause lies in the insufficient validation and sanitization of user-supplied input before it is rendered within HTML contexts by the application. When an attacker submits data through a vulnerable field, such as a meta description, title tag configuration, or other SEO-related settings managed by the plugin, the system fails to properly encode special characters like angle brackets, quotes, and ampersands. Consequently, when this untrusted input is retrieved from storage and displayed in subsequent web page generations, it is interpreted not as plain text but as executable JavaScript code by the victim's browser. This failure adheres closely to CWE-79, which defines improper neutralization of script-related HTML tags within a web page, allowing for arbitrary code execution in the context of the vulnerable site.
The operational impact of this vulnerability extends beyond simple defacement or session hijacking due to its stored nature. An attacker can craft payloads that steal administrative cookies, capture keystrokes, perform actions on behalf of authenticated users such as changing plugin settings or deleting content, and even redirect visitors to malicious phishing sites designed to harvest credentials. Because the FV Simpler SEO plugin is widely used for search engine optimization tasks, it often has access to high-level configuration areas within WordPress. If an attacker with lower privileges can inject this script, they may leverage cross-site request forgery techniques combined with the XSS payload to escalate their privileges or disrupt site integrity. Furthermore, since the malicious code persists in the database, the impact is continuous and affects all visitors until the vulnerable content is manually cleaned from the server, leading to potential widespread compromise of user sessions across multiple domains if cookie scopes are not strictly defined.
From a threat intelligence perspective, this vulnerability aligns with MITRE ATT&CK technique T1059.007, which covers JavaScript execution in web browsers. The attack vector typically involves an attacker identifying the vulnerable input field within the plugin’s administrative interface or potentially through front-end forms if they are exposed to public submission. Once the payload is stored, it becomes part of the legitimate content stream, making detection by standard security filters more difficult compared to reflected attacks where the malicious code appears only in a single request-response cycle. The persistence mechanism allows for long-term surveillance and data exfiltration campaigns against site administrators or regular users who interact with the compromised pages regularly.
Mitigation strategies must prioritize immediate remediation through software updates. Administrators running versions of FV Simpler SEO up to 1.9.7 should upgrade to a patched version where input sanitization has been rigorously implemented using established libraries such as OWASP Java Encoder or equivalent PHP functions like htmlspecialchars with appropriate flags for HTML entity encoding. In cases where immediate patching is not feasible, temporary workarounds include restricting access to the plugin’s configuration pages via strong authentication and IP whitelisting to prevent unauthorized users from injecting payloads. Additionally, implementing a Content Security Policy (CSP) header can significantly mitigate the impact by preventing the execution of inline scripts unless they originate from trusted sources, thereby neutralizing many XSS attacks even if input validation fails. Regular security audits and code reviews focusing on data flow between user inputs and HTML output are essential to prevent similar vulnerabilities in future development cycles.