diff -urd cosign-1.9.4/cgi/cgi.c cosign-1.9.4b/cgi/cgi.c
--- cosign-1.9.4/cgi/cgi.c	2005-11-01 18:07:38.000000000 -0500
+++ cosign-1.9.4b/cgi/cgi.c	2007-03-19 20:36:54.000000000 -0400
@@ -22,6 +22,7 @@
 #include "config.h"
 #include "login.h"
 #include "subfile.h"
+#include "mkcookie.h"
 
 #define SERVICE_MENU	"/services/"
 #define LOOPWINDOW      30 
@@ -309,7 +310,8 @@
 	goto loginscreen;
     }
 
-    if ( strlen( cookie ) < 120 ) {
+    len = strlen( cookie );
+    if ( len < 120 || len > 1024 ) {
 	goto loginscreen;
     }
 
diff -urd cosign-1.9.4/cgi/network.c cosign-1.9.4b/cgi/network.c
--- cosign-1.9.4/cgi/network.c	2005-05-13 16:19:46.000000000 -0400
+++ cosign-1.9.4b/cgi/network.c	2007-03-19 20:52:44.000000000 -0400
@@ -27,6 +27,7 @@
 #include "argcargv.h"
 #include "cosigncgi.h"
 #include "network.h"
+#include "mkcookie.h"
 
 static void (*logger)( char * ) = NULL;
 static struct timeval		timeout = { 10 * 60, 0 };
@@ -162,6 +163,10 @@
 {
     struct login_param lp;
 
+    if ( !validchars( cookie ) || !validchars( user )) {
+	return( -1 );
+    }
+
     lp.lp_cookie = cookie;
     lp.lp_ip = ip;
     lp.lp_user = user;
@@ -325,6 +330,9 @@
 {
     struct logout_param lp;
 
+    if ( !validchars( cookie )) {
+	return( -1 );
+    }
     lp.lp_cookie = cookie;
     lp.lp_ip = ip;
 
@@ -378,6 +386,10 @@
 
     struct reg_param rp;
 
+    if ( !validchars( cookie ) || !validchars( scookie )) {
+	return( -1 );
+    }
+
     rp.rp_cookie = cookie;
     rp.rp_ip = ip;
     rp.rp_scookie = scookie;
@@ -431,6 +443,10 @@
 {
     static struct check_param cp;
 
+    if ( !validchars( cookie )) {
+	return( -1 );
+    }
+
     cp.cp_cookie = cookie;
     *cp.cp_user = '\0';
 
diff -urd cosign-1.9.4/common/mkcookie.c cosign-1.9.4b/common/mkcookie.c
--- cosign-1.9.4/common/mkcookie.c	2005-11-01 12:15:52.000000000 -0500
+++ cosign-1.9.4b/common/mkcookie.c	2007-03-19 20:45:50.000000000 -0400
@@ -5,6 +5,54 @@
 #include "fbase64.h"
 #include "mkcookie.h"
 
+static char	valid_tab[ 256 ] = {
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 1, 0, 1, 1, 0,	/*             '+'     '-' '.'     */
+ 1, 1, 1, 1, 1, 1, 1, 1,	/* '0' '1' '2' '3' '4' '5' '6' '7' */
+ 1, 1, 0, 0, 0, 1, 0, 0,	/* '8' '9'             '='         */
+ 1, 1, 1, 1, 1, 1, 1, 1,	/* '@' 'A' 'B' 'C' 'D' 'E' 'F' 'G' */
+ 1, 1, 1, 1, 1, 1, 1, 1,	/* 'H' 'I' 'J' 'K' 'L' 'M' 'N' 'O' */
+ 1, 1, 1, 1, 1, 1, 1, 1,	/* 'P' 'Q' 'R' 'S' 'T' 'U' 'V' 'W' */
+ 1, 1, 1, 0, 0, 0, 0, 1,	/* 'X' 'Y' 'Z'                 '_' */
+ 0, 1, 1, 1, 1, 1, 1, 1,	/*     'a' 'b' 'c' 'd' 'e' 'f' 'g' */
+ 1, 1, 1, 1, 1, 1, 1, 1,	/* 'h' 'i' 'j' 'k' 'l' 'm' 'n' 'o' */
+ 1, 1, 1, 1, 1, 1, 1, 1,	/* 'p' 'q' 'r' 's' 't' 'u' 'v' 'w' */
+ 1, 1, 1, 0, 0, 0, 0, 0,	/* 'x' 'y' 'z'                     */
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+};
+
+    int
+validchars( char *s )
+{
+    char	*p;
+
+    for ( p = s; *p != '\0'; p++ ) {
+	if ( !valid_tab[ (unsigned char)*p ] ) {
+	    return( 0 );
+	}
+    }
+    return( 1 );
+}
+
     int
 mkcookie( int len, char *buf )
 {
diff -urd cosign-1.9.4/common/mkcookie.h cosign-1.9.4b/common/mkcookie.h
--- cosign-1.9.4/common/mkcookie.h	2005-11-01 12:15:52.000000000 -0500
+++ cosign-1.9.4b/common/mkcookie.h	2007-03-19 20:36:26.000000000 -0400
@@ -5,6 +5,7 @@
 
 int mkcookie( int, char * );
 int mkcookiepath( char *, int, char *, char *, int );
+int validchars( char * );
 
 #define MAXCOOKIELEN    1024
 
diff -urd cosign-1.9.4/filters/apache/mod_cosign.c cosign-1.9.4b/filters/apache/mod_cosign.c
--- cosign-1.9.4/filters/apache/mod_cosign.c	2005-11-11 16:50:47.000000000 -0500
+++ cosign-1.9.4b/filters/apache/mod_cosign.c	2007-03-19 20:42:28.000000000 -0400
@@ -304,6 +304,10 @@
 	goto set_cookie;
     }
 
+    if ( !validchars( my_cookie )) {
+	goto set_cookie;
+    }
+
     /*
      * Validate cookie with backside server.  If we already have a cached
      * version of the data, just verify the cookie's still valid.
diff -urd cosign-1.9.4/filters/apache2/mod_cosign.c cosign-1.9.4b/filters/apache2/mod_cosign.c
--- cosign-1.9.4/filters/apache2/mod_cosign.c	2005-11-08 23:16:25.000000000 -0500
+++ cosign-1.9.4b/filters/apache2/mod_cosign.c	2007-03-19 20:42:39.000000000 -0400
@@ -317,6 +317,10 @@
         goto set_cookie;
     }
 
+    if ( !validchars( my_cookie )) {
+	goto set_cookie;
+    }
+
     /*
      * Validate cookie with backside server.  If we already have a cached
      * version of the data, just verify the cookie's still valid.