CVE-2026-62084 in User Submitted Posts Plugin
Summary
by MITRE • 09/30/2026
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Jeff Starr User Submitted Posts allows Stored XSS.
This issue affects User Submitted Posts: from n/a through 20260810.
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Analysis
by VulDB Data Team • 09/30/2026
The identified security flaw represents a classic instance of Improper Neutralization of Input During Web Page Generation, commonly known as Cross-Site Scripting or XSS. Specifically, this vulnerability manifests within the Jeff Starr User Submitted Posts plugin for WordPress, allowing attackers to inject malicious client-side scripts into web pages viewed by other users. This particular iteration is classified as Stored XSS, which distinguishes it from reflected variants by persisting the malicious payload on the target server rather than merely passing it through a URL parameter or form submission that triggers an immediate response. The vulnerability exists because the application fails to adequately sanitize or validate user-supplied input before rendering it in HTML context, thereby allowing arbitrary JavaScript execution within the victim's browser session under the authority of the vulnerable website.
From a technical perspective, the root cause lies in insufficient output encoding and lack of strict input validation mechanisms during the processing of submitted content. When an attacker submits a post containing malicious script tags or event handlers such as onload or onerror attributes, the application stores this data directly into its database without applying necessary escaping functions like htmlspecialchars or equivalent context-aware sanitization routines. Consequently, when another user accesses the page displaying the compromised submission, their browser interprets the injected code as legitimate content belonging to the site's domain. This bypasses same-origin policy protections and grants the attacker significant control over the victim’s interaction with the application environment.
The operational impact of this Stored XSS vulnerability is severe due to its persistent nature. Unlike reflected attacks that require social engineering tactics to lure a specific target into clicking a crafted link, stored vulnerabilities automatically affect every user who views the infected content. Attackers can exploit this vector to steal session cookies, hijack administrative accounts if they view the compromised page while logged in with elevated privileges, or perform actions on behalf of victims such as changing settings, deleting data, or redirecting users to phishing sites. Furthermore, because the payload is stored server-side, it remains active until manually removed by an administrator, creating a long-term risk surface that can compromise multiple users over time without further intervention from the attacker.
This vulnerability aligns with CWE-79, which defines Improper Neutralization of Script-Related HTML Tags in Web Pages, and maps directly to MITRE ATT&CK technique T1059.007, specifically Command and Scripting Interpreter via JavaScript within a browser context. The persistence mechanism also correlates with data manipulation tactics where attackers alter stored information to achieve malicious goals without immediate detection by system administrators who may not monitor content submissions closely enough for embedded scripts.
Mitigation strategies must focus on both input validation and output encoding practices. Developers should implement strict allow-listing of permitted HTML tags and attributes, ensuring that any user-generated content is stripped of executable script elements before storage or display. Utilizing robust sanitization libraries designed to handle complex edge cases in HTML parsing can prevent injection attempts from succeeding at the code level. Additionally, implementing Content Security Policy headers with nonces or strict-directive configurations provides a critical layer of defense by restricting where scripts can be loaded from and preventing inline script execution even if an attacker manages to inject malicious markup. Upgrading to patched versions of the plugin that address these sanitization gaps is essential for immediate remediation while long-term architectural improvements ensure resilience against similar injection flaws across all user-facing inputs.