The vulnerability is a missing authentication flaw that permits any unauthenticated remote attacker to read and modify the mail content of any user. This weakness can lead to complete compromise of confidentiality and integrity of user data.

The affected product is HGiga's C&Cm@il mail application, delivered as the olln-base package. Systems running versions of olln-base earlier than 7.0‑978 are vulnerable; upgrading to version 7.0‑978 or later is required for remediation.

The CVSS score of 9.3 indicates critical severity, while the EPSS score of less than 1% suggests that exploitation is unlikely at present. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog, but its attack vector is remote and does not require authentication, making it highly attractive for attackers who succeed. The potential impact spans enterprise-wide exposure of sensitive email contents and unauthorized modification of communications.