Description

The MasterStudy LMS WordPress Plugin WordPress plugin before 3.7.43 does not validate a redirect parameter supplied during user registration before using it, allowing unauthenticated attackers to redirect users to arbitrary external URLs.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.7",
  "pubDate": "2026-08-29T06:17:58.700Z",
  "pubdate": "2026-08-29T06:17:58.700Z",
  "executiveSummary": "The MasterStudy LMS WordPress plugin before version 3.7.43 contains an Open Redirect vulnerability during the user registration process. This security flaw stems from the application's failure to properly validate user-supplied input intended for redirect parameters. By manipulating these parameters, an unauthenticated attacker can coerce the application into redirecting users to arbitrary, potentially malicious, external domains.\nThis vulnerability is classified as an Open Redirect, which facilitates social engineering and phishing campaigns by leveraging the trust associated with the legitimate domain. Since the redirect mechanism does not verify the destination against a whitelist or origin, attackers can craft deceptive URLs that appear legitimate to the end user. The impact includes the compromise of user trust, credential theft through spoofed landing pages, and the potential for bypassing security filters. Given that this vulnerability can be exploited by unauthenticated remote attackers, it presents a significant risk to the security posture of the WordPress instance and its user base. Users are strongly advised to update to the remediated version to mitigate the risk of exploitation.",
  "technicalDetails": "The vulnerability originates from a failure in input sanitization and validation logic within the MasterStudy LMS WordPress plugin registration workflow. Specifically, the component responsible for processing user registration fails to restrict the 'redirect' parameter to local or trusted URLs. In web applications, the registration or login flow often utilizes a redirect parameter to return users to the previously accessed page or a defined dashboard upon successful completion of the action. If the application blindly trusts this parameter, it becomes susceptible to manipulation.\nIn the context of the MasterStudy LMS plugin, an attacker can construct a crafted HTTP request containing a malicious URL within the registration endpoint's redirect parameter. Because the application logic does not perform a URL validation check (such as validating that the host matches the expected site domain), the server-side response instructs the victim's browser to navigate to the attacker-controlled URI. The flow of the attack is as follows: 1) The attacker identifies the vulnerable registration endpoint within the MasterStudy LMS plugin. 2) The attacker crafts a payload where the redirect parameter points to an external, malicious server. 3) The attacker distributes this URL to potential victims, often masking it via URL shorteners or social engineering tactics. 4) When an unsuspecting user interacts with the link and completes the registration process, the server-side code executes the redirect command using the attacker-supplied parameter. 5) The victim's browser initiates an HTTP GET request to the external malicious domain. 6) The external domain serves deceptive content, such as a credential harvester, malware delivery vector, or phishing site, while appearing to originate from the trusted domain of the legitimate LMS site.\nThe vulnerability is present in all versions prior to 3.7.43. It requires no authentication to execute, and the attack vector is exposed over the public network. Since the redirection occurs on the client-side via server-provided headers or scripts, there are no specific privilege requirements for the attacker. The primary post-exploitation impact is the successful redirection of users to arbitrary external sites, which facilitates broader phishing attacks, malicious traffic redirection, and severe reputation damage for the site owner."
}