commit - 4676ea2acb5a1129ec3c28ba660b60f19e2869ec
commit + 4678774c426670448c60935026a79634b84003a5
blob - cb99ad6c6929cf74bc2f830add5f7eeff78cdb2c
blob + 72b7bc3b70344d5614b2918026fd5848e9be1915
--- aliases/aliases.go
+++ aliases/aliases.go
@@ -94,6 +94,9 @@ func parseLine(s string) (recipient, destination strin
 	if !strings.HasSuffix(a[0], ":") {
 		return "", "", fmt.Errorf("parse line: invalid recipient: expected %q, got %q", ":", recipient[len(recipient)])
 	}
+	if strings.Contains(recipient, ":") {
+		return "", "", errors.New("parse line: recipient contains colon character")
+	}
 	if recipient == "" {
 		return "", "", errors.New("parse line: empty recipient")
 	}