CVE-2026-112207 in Download Monitor Plugin
Summary
by MITRE • 10/24/2026
The Download Monitor WordPress plugin before 5.3.4 does not properly validate that a clicked link belongs to the site before fetching it client-side and rendering part of the response in the page, which allows unauthenticated attackers to execute arbitrary JavaScript in the browser of any user who is tricked into clicking a crafted link.
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Analysis
by VulDB Data Team • 10/24/2026
The vulnerability identified in Download Monitor versions prior to 5.3.4 represents a critical security flaw rooted in insufficient input validation and improper handling of external resources within a widely used WordPress plugin environment. This specific weakness allows unauthenticated attackers to conduct Cross-Site Scripting attacks by exploiting the way the plugin processes user-supplied URLs during download operations. The core technical failure lies in the application's logic, which fails to verify that a requested link originates from a trusted domain or belongs to the site itself before initiating a client-side fetch request. By bypassing these essential security checks, an attacker can manipulate the plugin into retrieving content from malicious external servers and subsequently injecting that content directly into the browser context of any victim who interacts with the crafted payload.
From a technical perspective, this flaw is classified under CWE-79, which covers Improper Neutralization of Input During Web Page Generation commonly known as Cross-Site Scripting or XSS. The vulnerability operates through an open redirect mechanism combined with reflected script execution. When a user clicks on a specially constructed link controlled by the attacker, the plugin attempts to fetch the resource associated with that URL without performing adequate domain validation checks against its allowlist of trusted origins. Once the malicious content is fetched client-side, it is rendered within the page context, allowing arbitrary JavaScript code to execute in the victim's browser session. This execution occurs under the security privileges of the targeted website, enabling the attacker to bypass same-origin policy restrictions and interact with sensitive elements on the page as if they were a legitimate user.
The operational impact of this vulnerability is severe due to its unauthenticated nature and ease of exploitation. Attackers do not require any prior credentials or administrative access to trigger the flaw; instead, success relies solely on social engineering tactics such as tricking users into clicking malicious links via email, phishing campaigns, or compromised websites. Once executed, the arbitrary JavaScript can be leveraged for various malicious purposes including session hijacking, where attackers steal authentication cookies and tokens to impersonate legitimate users. It also facilitates credential harvesting by displaying fake login forms that capture usernames and passwords, data exfiltration of sensitive information stored in local storage or accessible via DOM manipulation, and defacement of the website's appearance. In enterprise environments using WordPress for internal portals, this could lead to significant compromise of organizational data and infrastructure integrity.
This vulnerability aligns with several tactics within the MITRE ATT&CK framework, specifically T1059 which covers Command and Scripting Interpreter execution via browser-based scripts, and T1189 Drive-by Client Execution where malicious code is delivered without user interaction beyond clicking a link. The lack of proper validation on external resources also reflects weaknesses in input handling that are often associated with CWE-20 Improper Input Validation. To mitigate this risk, administrators must immediately update the Download Monitor plugin to version 5.3.4 or later which addresses these validation gaps. Additionally, implementing Content Security Policy headers can help restrict script execution sources and reduce the impact of successful XSS attempts even if other vulnerabilities exist in the application stack. Regular security audits focusing on how third-party plugins handle external URLs are recommended to prevent similar issues across WordPress ecosystems.