diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
index 743c73200..a3ee5cf71 100644
--- a/winsup/cygwin/exceptions.cc
+++ b/winsup/cygwin/exceptions.cc
@@ -280,7 +280,7 @@ __unwind_single_frame (PCONTEXT ctx)
 {
   PRUNTIME_FUNCTION f;
   ULONG64 imagebase;
-  UNWIND_HISTORY_TABLE hist;
+  UNWIND_HISTORY_TABLE hist = {0};
   DWORD64 establisher;
   PVOID hdl;