diff --git a/src/merge/cluster_helper.cpp b/src/merge/cluster_helper.cpp
index b3fd34fcd..88bcf8246 100644
--- a/src/merge/cluster_helper.cpp
+++ b/src/merge/cluster_helper.cpp
@@ -43,6 +43,13 @@ cluster_helper_c::cluster_helper_c()
 }
 
 cluster_helper_c::~cluster_helper_c() {
+  // If rendering fails e.g. due to the file system being full, the
+  // cleanup code can run into access-after-free and
+  // free-multiple-times situations due to blocks still being present
+  // in the cluster. Therefore just dump them as cluster_helper_c is a
+  // singleton class.
+  if (m && m->cluster)
+    m->cluster->RemoveAll();
 }
 
 mm_io_c *
@@ -372,7 +379,7 @@ cluster_helper_c::must_duration_be_set(render_groups_c *rg,
 int
 cluster_helper_c::render() {
   std::vector<render_groups_cptr> render_groups;
-  KaxCues cues;
+  kax_cues_with_cleanup_c cues;
   cues.SetGlobalTimecodeScale(g_timecode_scale);
 
   bool use_simpleblock    = !hack_engaged(ENGAGE_NO_SIMPLE_BLOCKS);
diff --git a/src/merge/libmatroska_extensions.cpp b/src/merge/libmatroska_extensions.cpp
index 9033316d2..d480ee7c1 100644
--- a/src/merge/libmatroska_extensions.cpp
+++ b/src/merge/libmatroska_extensions.cpp
@@ -156,3 +156,15 @@ kax_cluster_c::delete_non_blocks() {
 
   RemoveAll();
 }
+
+kax_cues_with_cleanup_c::kax_cues_with_cleanup_c()
+  : KaxCues{}
+{
+}
+
+kax_cues_with_cleanup_c::~kax_cues_with_cleanup_c() {
+  // If rendering fails e.g. due to the file system being full,
+  // libmatroska may assert() due to myTempReferences being
+  // non-eempty. We don't care about that assertion.
+  myTempReferences.clear();
+}
diff --git a/src/merge/libmatroska_extensions.h b/src/merge/libmatroska_extensions.h
index b7a23204f..4cd000f69 100644
--- a/src/merge/libmatroska_extensions.h
+++ b/src/merge/libmatroska_extensions.h
@@ -92,4 +92,10 @@ public:
   }
 };
 
+class kax_cues_with_cleanup_c: public KaxCues {
+public:
+  kax_cues_with_cleanup_c();
+  virtual ~kax_cues_with_cleanup_c();
+};
+
 #endif // MTX_LIBMATROSKA_EXTENSIONS