diff --git a/ksh-20120801-bigsubst.patch b/ksh-20120801-bigsubst.patch
new file mode 100644
index 0000000..11b5363
--- /dev/null
+++ b/ksh-20120801-bigsubst.patch
@@ -0,0 +1,12 @@
+diff -up ksh-20120801/src/cmd/ksh93/sh/xec.c.bigsubst ksh-20120801/src/cmd/ksh93/sh/xec.c
+--- ksh-20120801/src/cmd/ksh93/sh/xec.c.bigsubst	2014-02-11 08:54:30.113556940 +0100
++++ ksh-20120801/src/cmd/ksh93/sh/xec.c	2014-02-11 08:54:30.141556816 +0100
+@@ -1772,7 +1772,7 @@ int sh_exec(register const Shnode_t *t,
+ 					}
+ 					if(shp->pipepid)
+ 						shp->pipepid = parent;
+-					else
++					else if(shp->comsub!=1)
+ 					{
+ 						job_wait(parent);
+ 						if(parent==shp->spid)
diff --git a/ksh.spec b/ksh.spec
index c4a439a..b6831c3 100644
--- a/ksh.spec
+++ b/ksh.spec
@@ -6,7 +6,7 @@ URL:          http://www.kornshell.com/
 Group:        System Environment/Shells
 License:      EPL
 Version:      20120801
-Release:      15%{?dist}
+Release:      16%{?dist}
 Source0:      http://www.research.att.com/~gsf/download/tgz/ast-ksh.%{releasedate}.tgz
 Source1:      http://www.research.att.com/~gsf/download/tgz/INIT.%{releasedate}.tgz
 Source2:      kshcomp.conf
@@ -33,6 +33,7 @@ Patch12: ksh-20130628-longer.patch
 
 # for ksh <= 2013-04-09, rhbz#960371
 Patch13: ksh-20120801-lexfix.patch
+Patch14: ksh-20120801-bigsubst.patch
 
 BuildRoot:    %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 Conflicts:    pdksh
@@ -65,6 +66,7 @@ with "sh" (the Bourne Shell).
 %patch11 -p1 -b .argvfix
 %patch12 -p1 -b .longer
 %patch13 -p1 -b .lexfix
+%patch14 -p1 -b .bigsubst
 
 #/dev/fd test does not work because of mock
 sed -i 's|ls /dev/fd|ls /proc/self/fd|' src/cmd/ksh93/features/options
@@ -159,6 +161,9 @@ fi
     rm -rf $RPM_BUILD_ROOT
 
 %changelog
+* Tue Feb 11 2014 Michal Hlavinka <mhlavink@redhat.com> - 20120801-16
+- ksh could hang when command substitution printed too much data
+
 * Thu Feb 06 2014 Michal Hlavinka <mhlavink@redhat.com> - 20120801-15
 - fix lexical parser crash (#960371)