diff --git a/NEWS b/NEWS
index 5348bda28a005..9a21a84e19917 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,8 @@ PHP                                                                        NEWS
     checks). (timwolla)
   . The __sleep() and __wakeup() magic methods have been deprecated. (Girgias)
   . Fixed hard_timeout with --enable-zend-max-execution-timers. (Appla)
+  . Fixed bug GH-19839 (Incorrect HASH_FLAG_HAS_EMPTY_IND flag on userland
+    array). (ilutov)
 
 - Curl:
   . Fix cloning of CURLOPT_POSTFIELDS when using the clone operator instead
diff --git a/Zend/tests/gh19839.phpt b/Zend/tests/gh19839.phpt
new file mode 100644
index 0000000000000..cc589ce0605f1
--- /dev/null
+++ b/Zend/tests/gh19839.phpt
@@ -0,0 +1,18 @@
+--TEST--
+GH-19839: Incorrect HASH_FLAG_HAS_EMPTY_IND flag on userland array
+--FILE--
+<?php
+
+const X = 'x';
+
+$x = null;
+unset(${X});
+
+$a = $GLOBALS;
+sort($a);
+serialize($a);
+
+?>
+===DONE===
+--EXPECT--
+===DONE===
diff --git a/Zend/zend_hash.c b/Zend/zend_hash.c
index d460c40b79714..6978beaa402e3 100644
--- a/Zend/zend_hash.c
+++ b/Zend/zend_hash.c
@@ -2464,6 +2464,7 @@ ZEND_API HashTable* ZEND_FASTCALL zend_array_dup(const HashTable *source)
 		target->nTableSize = HT_MIN_SIZE;
 		HT_SET_DATA_ADDR(target, &uninitialized_bucket);
 	} else if (GC_FLAGS(source) & IS_ARRAY_IMMUTABLE) {
+		ZEND_ASSERT(!(HT_FLAGS(source) & HASH_FLAG_HAS_EMPTY_IND));
 		HT_FLAGS(target) = HT_FLAGS(source) & HASH_FLAG_MASK;
 		target->nTableMask = source->nTableMask;
 		target->nNumUsed = source->nNumUsed;
@@ -2480,6 +2481,7 @@ ZEND_API HashTable* ZEND_FASTCALL zend_array_dup(const HashTable *source)
 			memcpy(HT_GET_DATA_ADDR(target), HT_GET_DATA_ADDR(source), HT_USED_SIZE(source));
 		}
 	} else if (HT_IS_PACKED(source)) {
+		ZEND_ASSERT(!(HT_FLAGS(source) & HASH_FLAG_HAS_EMPTY_IND));
 		HT_FLAGS(target) = HT_FLAGS(source) & HASH_FLAG_MASK;
 		target->nTableMask = HT_MIN_MASK;
 		target->nNumUsed = source->nNumUsed;
@@ -2499,7 +2501,8 @@ ZEND_API HashTable* ZEND_FASTCALL zend_array_dup(const HashTable *source)
 			zend_array_dup_packed_elements(source, target, 1);
 		}
 	} else {
-		HT_FLAGS(target) = HT_FLAGS(source) & HASH_FLAG_MASK;
+		/* Indirects are removed during duplication, remove HASH_FLAG_HAS_EMPTY_IND accordingly. */
+		HT_FLAGS(target) = HT_FLAGS(source) & (HASH_FLAG_MASK & ~HASH_FLAG_HAS_EMPTY_IND);
 		target->nTableMask = source->nTableMask;
 		target->nNextFreeElement = source->nNextFreeElement;
 		target->nInternalPointer =
diff --git a/Zend/zend_hash.h b/Zend/zend_hash.h
index 71206e61550bb..57020bbcad0b2 100644
--- a/Zend/zend_hash.h
+++ b/Zend/zend_hash.h
@@ -1621,14 +1621,15 @@ static zend_always_inline bool zend_array_is_list(const zend_array *array)
 }
 
 
-static zend_always_inline zval *_zend_hash_append_ex(HashTable *ht, zend_string *key, zval *zv, bool interned)
+static zend_always_inline zval *_zend_hash_append_ex(HashTable *ht, zend_string *key, zval *zv, bool key_guaranteed_interned)
 {
 	uint32_t idx = ht->nNumUsed++;
 	uint32_t nIndex;
 	Bucket *p = ht->arData + idx;
 
 	ZVAL_COPY_VALUE(&p->val, zv);
-	if (!interned && !ZSTR_IS_INTERNED(key)) {
+	ZEND_ASSERT(!key_guaranteed_interned || ZSTR_IS_INTERNED(key));
+	if (!key_guaranteed_interned && !ZSTR_IS_INTERNED(key)) {
 		HT_FLAGS(ht) &= ~HASH_FLAG_STATIC_KEYS;
 		zend_string_addref(key);
 		zend_string_hash_val(key);
@@ -1647,14 +1648,15 @@ static zend_always_inline zval *_zend_hash_append(HashTable *ht, zend_string *ke
 	return _zend_hash_append_ex(ht, key, zv, 0);
 }
 
-static zend_always_inline zval *_zend_hash_append_ptr_ex(HashTable *ht, zend_string *key, void *ptr, bool interned)
+static zend_always_inline zval *_zend_hash_append_ptr_ex(HashTable *ht, zend_string *key, void *ptr, bool key_guaranteed_interned)
 {
 	uint32_t idx = ht->nNumUsed++;
 	uint32_t nIndex;
 	Bucket *p = ht->arData + idx;
 
 	ZVAL_PTR(&p->val, ptr);
-	if (!interned && !ZSTR_IS_INTERNED(key)) {
+	ZEND_ASSERT(!key_guaranteed_interned || ZSTR_IS_INTERNED(key));
+	if (!key_guaranteed_interned && !ZSTR_IS_INTERNED(key)) {
 		HT_FLAGS(ht) &= ~HASH_FLAG_STATIC_KEYS;
 		zend_string_addref(key);
 		zend_string_hash_val(key);
diff --git a/sapi/fuzzer/fuzzer-sapi.c b/sapi/fuzzer/fuzzer-sapi.c
index b1909ef2f42fa..80915d0bbc19f 100644
--- a/sapi/fuzzer/fuzzer-sapi.c
+++ b/sapi/fuzzer/fuzzer-sapi.c
@@ -220,7 +220,9 @@ void fuzzer_request_shutdown(void)
 		zend_gc_collect_cycles();
 	} zend_end_try();
 
-	php_request_shutdown(NULL);
+	zend_try {
+		php_request_shutdown(NULL);
+	} zend_end_try();
 }
 
 /* Set up a dummy stack frame so that exceptions may be thrown. */