Microsoft Exchange 5.5 allows a remote attacker to relay email (i.e. spam) using encapsulated SMTP addresses, even if the anti-relaying features are enabled.
| Software | From | Fixed in |
|---|---|---|
| microsoft / exchange_server | 5.5 | 5.5.x |
| microsoft / exchange_server | 5.5-sp1 | 5.5-sp1.x |
| microsoft / exchange_server | 5.5-sp2 | 5.5-sp2.x |