SEPPmail versions before 15.0.5 process attachment filenames improperly during encrypted PDF generation, allowing an attacker to write a file outside the intended output directory. The flaw can lead to malicious files being placed in publicly accessible areas, potentially enabling web-based attacks or unauthorized data exposure.

The vulnerability affects all SEPPmail AG Secure Email Gateway installations running a version earlier than 15.0.5.

The CVSS score of 7.1 indicates a high severity, while the EPSS score below 1% suggests low current exploitation probability. The flaw is not listed in the CISA KEV catalog. Based on the description, it is inferred that attackers could target the PDF generation API remotely, creating files in web directories, which may enable further exploitation if the web server executes or serves these files.