Chris Butler

**Name of the Vulnerable Software and Affected Versions** Fail2ban version 0.8.3 **Description** The issue arises from an incorrect regular expression used in the filter.d/wuftpd.conf file, allowing remote attackers to cause a denial of service by forcing authentication failures. This can be achieved through a crafted reverse-resolved DNS name (rhost) entry that contains a substring interpreted as an IP address. **Recommendations** For Fail2ban version 0.8.3, update the filter.d/wuftpd.conf file with a corrected regular expression to prevent the exploitation of this issue. As a temporary workaround, consider restricting access to the affected configuration file to minimize the risk of exploitation.