OpenSIPS is a Session Initiation Protocol (SIP) server implementation. Prior to versions 3.1.9 and 3.2.6, if "ds_is_in_list()" is used with an invalid IP address string ("NULL" is illegal input), OpenSIPS will attempt to print a string from a random address (stack garbage), which could lead to a crash. All users of "ds_is_in_list()" without the "$si" variable as 1st parameter could be affected by this vulnerability to a larger, lesser or no extent at all, depending if the data passed to the function is a valid IPv4 or IPv6 address string or not. Fixes will are available starting with the 3.1.9 and 3.2.6 minor releases. There are no known workarounds.