An Open Redirect flaw exists in the Mautic form submission endpoint. After a visitor submits a form, the application blindly follows a return URL supplied by the form data, without confirming that the URL points to the Mautic instance or another trusted host. An attacker controlling the form can point the redirect to a phishing page or malware site, enabling credential theft or malicious payload delivery. The core weakness is a lack of input validation on redirect destinations, classified as CWE-601.

Any Mautic instance that has a published form exposed to the web is vulnerable. The vulnerability is present regardless of installation version; no specific version information is available, so all publicly available instances are considered at risk.

The CVSS score of 5.4 indicates a moderate severity; exploitation requires only an unauthenticated victim to submit a form crafted by the attacker. The EPSS score is not available, but the vulnerability is listed as not in the CISA KEV catalog, suggesting it is not a widely known exploited flaw. Attackers could use the open redirect to carry out phishing campaigns or deliver malware to users who legitimately interact with the form.