The slap_modrdn2mods function in modrdn.c in OpenLDAP 2.4.22 does not check the return value of a call to the smr_normalize function, which allows remote attackers to cause a denial of service (segmentation fault) and possibly execute arbitrary code via a modrdn call with an RDN string containing invalid UTF-8 sequences, which triggers a free of an invalid, uninitialized pointer in the slap_mods_free function, as demonstrated using the Codenomicon LDAPv3 test suite.