diff -up cracklib-2.9.6/lib/fascist.c.overflow cracklib-2.9.6/lib/fascist.c
--- cracklib-2.9.6/lib/fascist.c.overflow	2015-10-23 16:58:38.403319225 +0200
+++ cracklib-2.9.6/lib/fascist.c	2016-12-08 17:28:41.490101358 +0100
@@ -515,7 +515,7 @@ FascistGecosUser(char *password, const c
     char gbuffer[STRINGSIZE];
     char tbuffer[STRINGSIZE];
     char *uwords[STRINGSIZE];
-    char longbuffer[STRINGSIZE * 2];
+    char longbuffer[STRINGSIZE];
 
     if (gecos == NULL)
 	gecos = "";
@@ -596,38 +596,47 @@ FascistGecosUser(char *password, const c
     {
 	for (i = 0; i < j; i++)
 	{
-	    strcpy(longbuffer, uwords[i]);
-	    strcat(longbuffer, uwords[j]);
-
-	    if (GTry(longbuffer, password))
+	    if (strlen(uwords[i]) + strlen(uwords[j]) < STRINGSIZE)
 	    {
-		return _("it is derived from your password entry");
-	    }
-
-	    strcpy(longbuffer, uwords[j]);
-	    strcat(longbuffer, uwords[i]);
+		strcpy(longbuffer, uwords[i]);
+		strcat(longbuffer, uwords[j]);
 
-	    if (GTry(longbuffer, password))
-	    {
-		return _("it's derived from your password entry");
+		if (GTry(longbuffer, password))
+		{
+		    return _("it is derived from your password entry");
+		}
+
+		strcpy(longbuffer, uwords[j]);
+		strcat(longbuffer, uwords[i]);
+
+		if (GTry(longbuffer, password))
+		{
+		   return _("it's derived from your password entry");
+		}
 	    }
 
-	    longbuffer[0] = uwords[i][0];
-	    longbuffer[1] = '\0';
-	    strcat(longbuffer, uwords[j]);
-
-	    if (GTry(longbuffer, password))
+	    if (strlen(uwords[j]) < STRINGSIZE - 1)
 	    {
-		return _("it is derivable from your password entry");
+		longbuffer[0] = uwords[i][0];
+		longbuffer[1] = '\0';
+		strcat(longbuffer, uwords[j]);
+
+		if (GTry(longbuffer, password))
+		{
+		    return _("it is derivable from your password entry");
+		}
 	    }
 
-	    longbuffer[0] = uwords[j][0];
-	    longbuffer[1] = '\0';
-	    strcat(longbuffer, uwords[i]);
-
-	    if (GTry(longbuffer, password))
+	    if (strlen(uwords[i]) < STRINGSIZE - 1)
 	    {
-		return _("it's derivable from your password entry");
+		longbuffer[0] = uwords[j][0];
+		longbuffer[1] = '\0';
+		strcat(longbuffer, uwords[i]);
+
+		if (GTry(longbuffer, password))
+		{
+		    return _("it's derivable from your password entry");
+		}
 	    }
 	}
     }
diff -up cracklib-2.9.6/lib/rules.c.overflow cracklib-2.9.6/lib/rules.c
--- cracklib-2.9.6/lib/rules.c.overflow	2015-10-23 16:58:38.000000000 +0200
+++ cracklib-2.9.6/lib/rules.c	2016-12-08 18:03:27.041941297 +0100
@@ -158,6 +158,8 @@ Pluralise(string, area)		/* returns a po
     register int length;
     length = strlen(string);
     strcpy(area, string);
+    if (length > STRINGSIZE - 3) /* we add 2 characters at worst */
+	return (area);
 
     if (!Suffix(string, "ch") ||
 	!Suffix(string, "ex") ||
@@ -462,11 +464,11 @@ Mangle(input, control, area)		/* returns
 	    Pluralise(area2, area);
 	    break;
 	case RULE_REFLECT:
-	    strcat(area, Reverse(area, area2));
+	    strncat(area, Reverse(area, area2), STRINGSIZE - strlen(area) - 1);
 	    break;
 	case RULE_DUPLICATE:
 	    strcpy(area2, area);
-	    strcat(area, area2);
+	    strncat(area, area2, STRINGSIZE - strlen(area) - 1);
 	    break;
 	case RULE_GT:
 	    if (!ptr[1])
@@ -514,7 +516,8 @@ Mangle(input, control, area)		/* returns
 	    } else
 	    {
 		area2[0] = *(++ptr);
-		strcpy(area2 + 1, area);
+		strncpy(area2 + 1, area, STRINGSIZE - 2);
+		area2[STRINGSIZE - 1] = '\0';
 		strcpy(area, area2);
 	    }
 	    break;
@@ -528,8 +531,10 @@ Mangle(input, control, area)		/* returns
 		register char *string;
 		string = area;
 		while (*(string++));
-		string[-1] = *(++ptr);
-		*string = '\0';
+		if (string < area + STRINGSIZE) {
+			string[-1] = *(++ptr);
+			*string = '\0';
+		}
 	    }
 	    break;
 	case RULE_EXTRACT:
@@ -600,6 +605,10 @@ Mangle(input, control, area)		/* returns
 		}
 		p1 = area;
 		p2 = area2;
+		if (strlen(p1) > STRINGSIZE - 2) {
+			/* truncate */
+			p1[STRINGSIZE - 2] = '\0';
+		}
 		while (i && *p1)
 		{
 		    i--;