diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 55ea458f0..a8f654348 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,9 @@
+2015-07-23  Corinna Vinschen  <corinna@vinschen.de>
+
+	* exceptions.cc (__cont_link_context): x86_64: align stack and reserve
+	shadow space for subsequent function calls, otherwise suffer potential
+	buffer overflow.
+
 2015-07-23  Corinna Vinschen  <corinna@vinschen.de>
 
 	* uinfo.cc (cygheap_user::ontherange): Ignore $HOME if it's not
diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
index c4b076169..e6c000f3e 100644
--- a/winsup/cygwin/exceptions.cc
+++ b/winsup/cygwin/exceptions.cc
@@ -1929,9 +1929,14 @@ swapcontext (ucontext_t *oucp, const ucontext_t *ucp)
    is NULL, call exit. */
 __asm__ ("				\n\
 	.global	__cont_link_context	\n\
+	.seh_proc __cont_link_context	\n\
 __cont_link_context:			\n\
+	.seh_endprologue		\n\
 	movq	%rbx, %rsp		\n\
-	popq	%rcx			\n\
+	movq	(%rsp), %rcx		\n\
+	# align stack and subtract shadow space	\n\
+	andq	$~0xf, %rsp		\n\
+	subq	$0x20, %rsp		\n\
 	testq	%rcx, %rcx		\n\
 	je	1f			\n\
 	call	setcontext		\n\
@@ -1939,6 +1944,7 @@ __cont_link_context:			\n\
 1:					\n\
 	call	cygwin_exit		\n\
 	nop				\n\
+	.seh_endproc			\n\
 	");
 
 #else