A recent Bugtraq posting reported an issue with IMAP users having the ability to change the database quota on their own mail file via Telnet.
The advisory address is as follows:
This issue was reported to Quality Engineering as SPR# SEGN5VEFHE and has been addressed in Domino 6.0.5 and 6.5.4.
Excerpt from the Lotus Notes and Domino Release 6.5.4 and 6.0.5 MR fix list (available at http://www.ibm.com/developerworks/lotus/):
SPR# SEGN5VEFHE - Telnet users are no longer able to reset the database quota during a Telnet session.