CVE-2023-50456 is a medium-severity vulnerability identified in versions of Zammad prior to 6.2.0. Zammad is an open-source helpdesk and customer support platform widely used for ticketing and communication management. The vulnerability arises from insufficient sanitization or validation of user-supplied input fields, specifically the first or last name fields, which are incorporated into generated notification emails. An attacker can craft malicious input in these name fields that results in phishing links being embedded within notification emails sent by the system. This is classified as an open redirect vulnerability (CWE-601), where the attacker can manipulate URLs in emails to redirect recipients to malicious websites. The CVSS 3.1 base score of 5.3 reflects a network attack vector with low attack complexity, no privileges or user interaction required, and impacts integrity but not confidentiality or availability. Although no known exploits are currently reported in the wild, the vulnerability could be leveraged to conduct phishing campaigns targeting users of the Zammad platform by exploiting trust in notification emails. This could lead to credential theft, malware installation, or other social engineering attacks. The lack of a patch link indicates that users should upgrade to Zammad 6.2.0 or later once available or apply vendor-recommended mitigations to prevent injection of malicious links in user input fields.

For European organizations using Zammad as their helpdesk or customer support solution, this vulnerability poses a risk of phishing attacks delivered through legitimate notification emails. Such attacks could undermine user trust, lead to credential compromise, and facilitate further network intrusion or data exfiltration. Since Zammad is often integrated with internal ticketing and communication workflows, successful exploitation could disrupt operational processes and expose sensitive customer or internal information. The impact is particularly significant for organizations with large user bases receiving frequent notifications, as the attack surface is broad. Additionally, phishing attacks exploiting this vulnerability could be used as a vector for targeted attacks against European enterprises, potentially affecting sectors like finance, healthcare, and government where helpdesk systems are critical. The medium severity rating suggests a moderate but non-negligible risk, emphasizing the need for timely mitigation to prevent exploitation.

European organizations should prioritize upgrading Zammad installations to version 6.2.0 or later, where this vulnerability is addressed. Until an upgrade is possible, administrators should implement strict input validation and sanitization on user-supplied fields, especially first and last names, to block or neutralize malicious URL payloads. Email templates used for notifications should be reviewed and hardened to avoid rendering untrusted input as clickable links. Employing email security gateways with phishing detection and URL rewriting can help mitigate risk by warning users or blocking malicious links. User awareness training focused on recognizing phishing attempts originating from internal systems is also recommended. Monitoring email logs for unusual link patterns or spikes in phishing reports can provide early detection of exploitation attempts. Finally, organizations should maintain up-to-date incident response plans to quickly address any phishing incidents stemming from this vulnerability.