CVS 1.12 and earlier on Debian GNU/Linux does not properly handle when a mapping for the current repository does not exist in the cvs-repouids file, which allows remote attackers to cause a denial of service (server crash).
Heap-based buffer overflow in the proxyconnect function in src/client.c in CVS 1.11 and 1.12 allows remote HTTP proxy servers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted HTTP response.