diff --git a/ChangeLog b/ChangeLog
index b22845f95b..9fae94249e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+Sat May 21 05:43:03 2011  URABE Shyouhei  <shyouhei@ruby-lang.org>
+
+	* eval.c (rb_thread_atfork): When a ruby process forks, its random
+	  seed shall be reinitialized to prevent CVE-2003-0900 situation.
+	  This bug affects for 1.8 and earlier series, but not for 1.9.
+	  fixed [ruby-core:34944].
+
+	* io.c (pipe_open): ditto.
+
+	* random.c (rb_reset_random_seed): ditto.
+
+	* intern.h (rb_reset_random_seed): ditto.
+
 Sun May 15 21:43:09 2011  Akinori MUSHA  <knu@iDaemons.org>
 
 	* lib/uri/generic.rb (#route_from_path): Fix a bug where
diff --git a/eval.c b/eval.c
index a54fdce6b9..222a868b53 100644
--- a/eval.c
+++ b/eval.c
@@ -13515,6 +13515,7 @@ rb_thread_atfork()
 {
     rb_thread_t th;
 
+    rb_reset_random_seed();
     if (rb_thread_alone()) return;
     FOREACH_THREAD(th) {
 	if (th != curr_thread) {
diff --git a/intern.h b/intern.h
index 927cdf2ea2..321fb4cc18 100644
--- a/intern.h
+++ b/intern.h
@@ -392,6 +392,7 @@ VALUE rb_length_by_each _((VALUE));
 /* random.c */
 unsigned long rb_genrand_int32(void);
 double rb_genrand_real(void);
+void rb_reset_random_seed(void);
 /* re.c */
 int rb_memcmp _((const void*,const void*,long));
 int rb_memcicmp _((const void*,const void*,long));
diff --git a/io.c b/io.c
index f7f17c85fb..d40e570860 100644
--- a/io.c
+++ b/io.c
@@ -3274,6 +3274,7 @@ retry:
     rb_thread_stop_timer();
     switch ((pid = fork())) {
       case 0:			/* child */
+        rb_thread_atfork();
 	if (modef & FMODE_READABLE) {
 	    close(pr[0]);
 	    if (pr[1] != 1) {
diff --git a/random.c b/random.c
index 92ef3fcae5..45a94d0563 100644
--- a/random.c
+++ b/random.c
@@ -488,9 +488,15 @@ rb_f_rand(argc, argv, obj)
 }
 
 void
-Init_Random()
+rb_reset_random_seed()
 {
     rand_init(random_seed());
+}
+
+void
+Init_Random()
+{
+    rb_reset_random_seed();
     rb_define_global_function("srand", rb_f_srand, -1);
     rb_define_global_function("rand", rb_f_rand, -1);
     rb_global_variable(&saved_seed);