CVS 1.11.x before 1.11.17, and 1.12.x before 1.12.9, allows remote attackers to determine the existence of arbitrary files and directories via the -X command for an alternate history file, which causes different error messages to be returned.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10688
https://euvd.enisa.europa.eu/vulnerability/EUVD-2004-0776
http://www.securityfocus.com/bid/10955
http://www.mandrakesecure.net/en/advisories/advisory.php?name=MDKSA-2004:108
http://www.idefense.com/application/poi/display?id=130&type=vulnerabilities