diff --git a/mongoose.c b/mongoose.c
index 968613be..a3ac9d52 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -3280,6 +3280,7 @@ size_t mg_vprintf(struct mg_connection *c, const char *fmt, va_list ap) {
   va_list tmp;
   va_copy(tmp, ap);
   mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, &tmp);
+  va_end(tmp);
   return c->send.len - old;
 }
 
diff --git a/src/net.c b/src/net.c
index 63c830f1..3d22fea9 100644
--- a/src/net.c
+++ b/src/net.c
@@ -10,6 +10,7 @@ size_t mg_vprintf(struct mg_connection *c, const char *fmt, va_list ap) {
   va_list tmp;
   va_copy(tmp, ap);
   mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, &tmp);
+  va_end(tmp);
   return c->send.len - old;
 }