SEPPmail Secure Email Gateway before version 15.0.3 allows attackers with a specially crafted email address to claim another user's PGP signature as their own.
Exploitability
AV:NAC:LAT:PPR:NUI:NVulnerable System
VC:NVI:NVA:NSubsequent System
SC:NSI:LSA:N6.3/CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:NOther