When adding an external mail account, processing of SMTP “capabilities” responses are not limited to plausible sizes. Attacker with access to a rogue SMTP service could trigger requests that lead to excessive resource usage and eventually service unavailability. We now limit accepted SMTP server response to reasonable length/size. No publicly available exploits are known.
packetstormsecurity.com/files/173083/OX-App-Suite-SSRF-Resource-Consumption-Command-Injection.html
seclists.org/fulldisclosure/2023/Jun/8
documentation.open-xchange.com/appsuite/security/advisories/csaf/2023/oxas-adv-2023-0002.json
software.open-xchange.com/products/appsuite/doc/Release_Notes_for_Patch_Release_6219_7.10.6_2023-03-20.pdf