An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1. By sending a handcrafted message, a buffer overflow may happen. This can be used to execute code remotely.
4.90.1-1Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:HI:HA:HCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H