A number of vulnerabilities were discovered in CVS by Stefan Esser, Sebastian Krahmer, and Derek Price.
Insufficient input validation while processing "Entry" lines. (CVE-2004-0414) A double-free resulting from erroneous state handling while processing "Argumentx" commands. (CVE-2004-0416) Integer overflow while processing "Max-dotdot" commands. (CVE-2004-0417) Erroneous handling of empty entries handled while processing "Notify" commands. (CVE-2004-0418) A format string bug while processing CVS wrappers. Single-byte buffer underflows while processing configuration files from CVSROOT. Various other integer overflows.
Additionally, iDEFENSE reports an undocumented command-line flag used in debugging does not perform input validation on the given path names. CVS servers ("cvs server" or :pserver: modes) are affected by these vulnerabilities. They vary in impact but include information disclosure (the iDEFENSE-reported bug), denial-of-service (CVE-2004-0414, CVE-2004-0416, CVE-2004-0417 and other bugs), or possibly arbitrary code execution (CVE-2004-0418). In very special situations where the attacker may somehow influence the contents of CVS configuration files in CVSROOT, additional attacks may be possible.