diff --git a/dlls/msvcirt/msvcirt.c b/dlls/msvcirt/msvcirt.c
index b5fd19c39e6..170dcee462a 100644
--- a/dlls/msvcirt/msvcirt.c
+++ b/dlls/msvcirt/msvcirt.c
@@ -315,10 +315,10 @@ DEFINE_RTTI_DATA2(ifstream, sizeof(istream),
 DEFINE_RTTI_DATA4(iostream, sizeof(iostream),
     &istream_rtti_base_descriptor, &ios_rtti_base_descriptor,
     &ostream_rtti_base_descriptor, &ios_rtti_base_descriptor, ".?AViostream@@")
-DEFINE_RTTI_DATA4(strstream, sizeof(iostream),
+DEFINE_RTTI_DATA5(strstream, sizeof(iostream), &iostream_rtti_base_descriptor,
     &istream_rtti_base_descriptor, &ios_rtti_base_descriptor,
     &ostream_rtti_base_descriptor, &ios_rtti_base_descriptor, ".?AVstrstream@@")
-DEFINE_RTTI_DATA4(stdiostream, sizeof(iostream),
+DEFINE_RTTI_DATA5(stdiostream, sizeof(iostream), &iostream_rtti_base_descriptor,
     &istream_rtti_base_descriptor, &ios_rtti_base_descriptor,
     &ostream_rtti_base_descriptor, &ios_rtti_base_descriptor, ".?AVstdiostream@@")
 
diff --git a/dlls/msvcp90/cxx.h b/dlls/msvcp90/cxx.h
index 721d02c5487..02735a3c168 100644
--- a/dlls/msvcp90/cxx.h
+++ b/dlls/msvcp90/cxx.h
@@ -247,6 +247,8 @@ static void init_ ## type ## _cxx(char *base) \
     DEFINE_RTTI_DATA(name, off, 3, cl1, cl2, cl3, NULL, NULL, NULL, NULL, NULL, NULL, mangled_name)
 #define DEFINE_RTTI_DATA4(name, off, cl1, cl2, cl3, cl4, mangled_name) \
     DEFINE_RTTI_DATA(name, off, 4, cl1, cl2, cl3, cl4, NULL, NULL, NULL, NULL, NULL, mangled_name)
+#define DEFINE_RTTI_DATA5(name, off, cl1, cl2, cl3, cl4, cl5, mangled_name) \
+    DEFINE_RTTI_DATA(name, off, 5, cl1, cl2, cl3, cl4, cl5, NULL, NULL, NULL, NULL, mangled_name)
 #define DEFINE_RTTI_DATA8(name, off, cl1, cl2, cl3, cl4, cl5, cl6, cl7, cl8, mangled_name) \
     DEFINE_RTTI_DATA(name, off, 8, cl1, cl2, cl3, cl4, cl5, cl6, cl7, cl8, NULL, mangled_name)
 #define DEFINE_RTTI_DATA9(name, off, cl1, cl2, cl3, cl4, cl5, cl6, cl7, cl8, cl9, mangled_name) \