http://ftp.de.debian.org/debian/pool/main/libn/libnet/libnet_1.1.4-2.diff.gz NULLify pointers after free()ing them to avoid double free()s. Index: libnet-1.1.4/src/libnet_if_addr.c =================================================================== --- libnet-1.1.4.orig/src/libnet_if_addr.c 2009-06-27 14:48:56.084093427 +0300 +++ libnet-1.1.4/src/libnet_if_addr.c 2009-06-27 14:49:30.081249393 +0300 @@ -240,6 +240,7 @@ { /* fix memory leak */ free(al->device); + al->device = NULL; } if ((al->device = strdup(device)) == NULL) { @@ -406,6 +407,7 @@ for (i = 0; i < c; i++) { free(al[i].device); + al[i].device = NULL; } return (1); @@ -413,6 +415,7 @@ for (i = 0; i < c; i++) { free(al[i].device); + al[i].device = NULL; } return (-1); }