The modoboa-dmarc plugin 1.1.0 for Modoboa is vulnerable to an XML External Entity Injection (XXE) attack when processing XML data. A remote attacker could exploit this to perform a denial of service against the DMARC reporting functionality, such as by referencing the /dev/random file within XML documents that are emailed to the address in the rua field of the DMARC records of a domain.