diff --git a/3rdParty/velocypack/include/velocypack/Iterator.h b/3rdParty/velocypack/include/velocypack/Iterator.h
index a6fe3db147..724dc5f059 100644
--- a/3rdParty/velocypack/include/velocypack/Iterator.h
+++ b/3rdParty/velocypack/include/velocypack/Iterator.h
@@ -157,6 +157,7 @@ class ArrayIterator {
     _current = nullptr;
     if (_size > 0) {
       auto h = _slice.head();
+      VELOCYPACK_ASSERT(h != 0x01); // no empty array allowed here
       if (h == 0x13) {
         _current = _slice.at(0).start();
       } else {
@@ -194,6 +195,7 @@ class ObjectIterator {
 
     if (_size > 0) {
       auto h = slice.head();
+      VELOCYPACK_ASSERT(h != 0x0a); // no empty object allowed here
       if (h == 0x14) {
         _current = slice.keyAt(0, false).start();
       } else if (useSequentialIteration) {
diff --git a/3rdParty/velocypack/include/velocypack/Slice.h b/3rdParty/velocypack/include/velocypack/Slice.h
index c6c697d28d..8d7cf1031d 100644
--- a/3rdParty/velocypack/include/velocypack/Slice.h
+++ b/3rdParty/velocypack/include/velocypack/Slice.h
@@ -379,6 +379,7 @@ class Slice {
 
     // find number of items
     if (h <= 0x05) {  // No offset table or length, need to compute:
+      VELOCYPACK_ASSERT(h != 0x00 && h != 0x01);
       ValueLength firstSubOffset = findDataOffset(h);
       Slice first(_start + firstSubOffset);
       ValueLength s = first.byteSize();
@@ -848,9 +849,14 @@ class Slice {
   }
   
   ValueLength findDataOffset(uint8_t head) const noexcept {
-    // Must be called for a nonempty array or object at start():
-    VELOCYPACK_ASSERT(head <= 0x12);
+    // Must be called for a non-empty array or object at start():
+    VELOCYPACK_ASSERT(head != 0x01 && head != 0x0a && head <= 0x14);
     unsigned int fsm = SliceStaticData::FirstSubMap[head];
+    if (fsm == 0) {
+      // need to calculate the offset by reading the dynamic length
+      VELOCYPACK_ASSERT(head == 0x13 || head == 0x14);
+      return 1 + readVariableValueLength<false>(_start + 1);
+    }
     if (fsm <= 2 && _start[2] != 0) {
       return 2;
     }
diff --git a/3rdParty/velocypack/src/Slice.cpp b/3rdParty/velocypack/src/Slice.cpp
index 16f608ee18..298437ba67 100644
--- a/3rdParty/velocypack/src/Slice.cpp
+++ b/3rdParty/velocypack/src/Slice.cpp
@@ -340,7 +340,9 @@ unsigned int const SliceStaticData::FirstSubMap[32] = {
     3,  // 0x0f, object with unsorted index table
     5,  // 0x10, object with unsorted index table
     9,  // 0x11, object with unsorted index table
-    9,  // 0x12, object with unsorted index table
+    9,  // 0x12, object with unsorted index table,
+    0,  // 0x13, compact array, no index table - note: the offset is dynamic!
+    0,  // 0x14, compact object, no index table - note: the offset is dynamic!
     0};
 
 // creates a Slice from Json and adds it to a scope
diff --git a/arangod/Transaction/Helpers.cpp b/arangod/Transaction/Helpers.cpp
index b2a2463560..5010703aea 100644
--- a/arangod/Transaction/Helpers.cpp
+++ b/arangod/Transaction/Helpers.cpp
@@ -102,6 +102,10 @@ std::string transaction::helpers::extractIdString(CollectionNameResolver const*
    
   if (slice.isObject()) {
     // extract id attribute from object
+    if (slice.isEmptyObject()) {
+      THROW_ARANGO_EXCEPTION(TRI_ERROR_ARANGO_DOCUMENT_TYPE_INVALID);
+    }
+
     uint8_t const* p = slice.begin() + slice.findDataOffset(slice.head());
     if (*p == basics::VelocyPackHelper::KeyAttribute) {
       // skip over attribute name
@@ -115,7 +119,7 @@ std::string transaction::helpers::extractIdString(CollectionNameResolver const*
         if (id.isCustom()) {
           // we should be pointing to a custom value now
           TRI_ASSERT(id.head() == 0xf3);
- 
+
           return makeIdFromCustom(resolver, id, key);
         }
         if (id.isString()) {