diff --git a/Zend/tests/in-de-crement/oss-fuzz-61865_binop_declared_property_unset_error_handler.phpt b/Zend/tests/in-de-crement/oss-fuzz-61865_binop_declared_property_unset_error_handler.phpt
new file mode 100644
index 0000000000000..c5a9fe3c8032a
--- /dev/null
+++ b/Zend/tests/in-de-crement/oss-fuzz-61865_binop_declared_property_unset_error_handler.phpt
@@ -0,0 +1,18 @@
+--TEST--
+OSS Fuzz #61865: Undef variable in ++/-- for declared property that is unset in error handler
+--FILE--
+<?php
+class C {
+    public $a;
+    function errorHandler($errno, $errstr) {
+        unset($this->a);
+    }
+}
+$c = new C;
+set_error_handler([$c,'errorHandler']);
+unset($c->a);
+$c->a += 5;
+var_dump($c->a);
+?>
+--EXPECT--
+int(5)
diff --git a/Zend/tests/in-de-crement/oss-fuzz-61865_postdec_declared_property_unset_error_handler.phpt b/Zend/tests/in-de-crement/oss-fuzz-61865_postdec_declared_property_unset_error_handler.phpt
new file mode 100644
index 0000000000000..6fb1d18f69492
--- /dev/null
+++ b/Zend/tests/in-de-crement/oss-fuzz-61865_postdec_declared_property_unset_error_handler.phpt
@@ -0,0 +1,20 @@
+--TEST--
+OSS Fuzz #61865: Undef variable in ++/-- for declared property that is unset in error handler
+--FILE--
+<?php
+class C {
+    public $a;
+    function errorHandler($errno, $errstr) {
+        unset($this->a);
+    }
+}
+$c = new C;
+set_error_handler([$c,'errorHandler']);
+unset($c->a);
+$v = ($c->a--);
+var_dump($c->a);
+var_dump($v);
+?>
+--EXPECT--
+NULL
+NULL
diff --git a/Zend/tests/in-de-crement/oss-fuzz-61865_postinc_declared_property_unset_error_handler.phpt b/Zend/tests/in-de-crement/oss-fuzz-61865_postinc_declared_property_unset_error_handler.phpt
new file mode 100644
index 0000000000000..94bccd7a82f80
--- /dev/null
+++ b/Zend/tests/in-de-crement/oss-fuzz-61865_postinc_declared_property_unset_error_handler.phpt
@@ -0,0 +1,20 @@
+--TEST--
+OSS Fuzz #61865: Undef variable in ++/-- for declared property that is unset in error handler
+--FILE--
+<?php
+class C {
+    public $a;
+    function errorHandler($errno, $errstr) {
+        unset($this->a);
+    }
+}
+$c = new C;
+set_error_handler([$c,'errorHandler']);
+unset($c->a);
+$v = ($c->a++);
+var_dump($c->a);
+var_dump($v);
+?>
+--EXPECT--
+int(1)
+NULL
diff --git a/Zend/tests/in-de-crement/oss-fuzz-61865_predec_declared_property_unset_error_handler.phpt b/Zend/tests/in-de-crement/oss-fuzz-61865_predec_declared_property_unset_error_handler.phpt
new file mode 100644
index 0000000000000..f077ecb53dcad
--- /dev/null
+++ b/Zend/tests/in-de-crement/oss-fuzz-61865_predec_declared_property_unset_error_handler.phpt
@@ -0,0 +1,18 @@
+--TEST--
+OSS Fuzz #61865: Undef variable in ++/-- for declared property that is unset in error handler
+--FILE--
+<?php
+class C {
+    public $a;
+    function errorHandler($errno, $errstr) {
+        unset($this->a);
+    }
+}
+$c = new C;
+set_error_handler([$c,'errorHandler']);
+unset($c->a);
+(--$c->a);
+var_dump($c->a);
+?>
+--EXPECT--
+NULL
diff --git a/Zend/tests/in-de-crement/oss-fuzz-61865_preinc_declared_property_unset_error_handler.phpt b/Zend/tests/in-de-crement/oss-fuzz-61865_preinc_declared_property_unset_error_handler.phpt
new file mode 100644
index 0000000000000..a63e08e49c9dc
--- /dev/null
+++ b/Zend/tests/in-de-crement/oss-fuzz-61865_preinc_declared_property_unset_error_handler.phpt
@@ -0,0 +1,18 @@
+--TEST--
+OSS Fuzz #61865: Undef variable in ++/-- for declared property that is unset in error handler
+--FILE--
+<?php
+class C {
+    public $a;
+    function errorHandler($errno, $errstr) {
+        unset($this->a);
+    }
+}
+$c = new C;
+set_error_handler([$c,'errorHandler']);
+unset($c->a);
+(++$c->a);
+var_dump($c->a);
+?>
+--EXPECT--
+int(1)
diff --git a/Zend/tests/in-de-crement/unset_property_converted_to_obj_in_error_handler.phpt b/Zend/tests/in-de-crement/unset_property_converted_to_obj_in_error_handler.phpt
new file mode 100644
index 0000000000000..d435c9fb4029e
--- /dev/null
+++ b/Zend/tests/in-de-crement/unset_property_converted_to_obj_in_error_handler.phpt
@@ -0,0 +1,25 @@
+--TEST--
+Unset declared property converted to object in error handler
+--FILE--
+<?php
+class C {
+    public $a;
+    function errorHandler() {
+        $this->a = new stdClass();
+    }
+}
+$c = new C;
+set_error_handler([$c,'errorHandler']);
+unset($c->a);
+
+try {
+    (++$c->a);
+} catch (\TypeError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+var_dump($c->a);
+?>
+--EXPECT--
+Cannot increment stdClass
+object(stdClass)#2 (0) {
+}
diff --git a/Zend/zend_object_handlers.c b/Zend/zend_object_handlers.c
index 5146b0864916d..573d9eb106df1 100644
--- a/Zend/zend_object_handlers.c
+++ b/Zend/zend_object_handlers.c
@@ -1117,8 +1117,11 @@ ZEND_API zval *zend_std_get_property_ptr_ptr(zend_object *zobj, zend_string *nam
 							ZSTR_VAL(name));
 						retval = &EG(error_zval);
 					} else {
-						ZVAL_NULL(retval);
 						zend_error(E_WARNING, "Undefined property: %s::$%s", ZSTR_VAL(zobj->ce->name), ZSTR_VAL(name));
+						/* An error handler may set the property */
+						 if (EXPECTED(Z_TYPE_P(retval) == IS_UNDEF)) {
+							ZVAL_NULL(retval);
+						 }
 					}
 				} else if (prop_info && UNEXPECTED(prop_info->flags & ZEND_ACC_READONLY)) {
 					/* Readonly property, delegate to read_property + write_property. */