The (1) memc_save_get_next_page (2) tmemc_restore_put_page and (3) tmemc_restore_flush_page functions in the Transcendent Memory (TMEM) in Xen 4.0 4.1 and 4.2 do not check for negative id pools which allows local guest OS users to cause a denial of service (memory corruption and host crash) or possibly execute arbitrary code via unspecified vectors. NOTE: this issue was originally published as part of CVE-2012-3497 which was too general; CVE-2012-3497 has been SPLIT into this ID and others.