diff --git a/NEWS b/NEWS
index 40393c15fb76..6c615b944baf 100644
--- a/NEWS
+++ b/NEWS
@@ -77,6 +77,10 @@ PHP                                                                        NEWS
   . Fixed grapheme_strrpos() and grapheme_strripos() skipping overlapping matches
     when using a negative offset. (Weilin Du)
 
+- JSON:
+  . Fixed json_encode() continuing to encode after an array or object key
+    failed to encode. (Ilia Alshanetsky)
+
 - Lexbor:
   . Merge patches lexbor/lexbor@8a14bc0 and lexbor/lexbor@f67ce4b, fixing a
     heap buffer overflow in :lexbor-contains() parsing and buffer overflows
diff --git a/ext/json/json_encoder.c b/ext/json/json_encoder.c
index cefee25de90a..e763a7d2052e 100644
--- a/ext/json/json_encoder.c
+++ b/ext/json/json_encoder.c
@@ -186,11 +186,15 @@ static zend_result php_json_encode_array(smart_str *buf, zval *val, int options,
 			php_json_pretty_print_indent(buf, options, encoder);
 
 			if (php_json_escape_string(buf, ZSTR_VAL(prop_info->name), ZSTR_LEN(prop_info->name),
-					options & ~PHP_JSON_NUMERIC_CHECK, encoder) == FAILURE &&
-					(options & PHP_JSON_PARTIAL_OUTPUT_ON_ERROR) &&
-					buf->s) {
-				ZSTR_LEN(buf->s) -= 4;
-				smart_str_appendl(buf, "\"\"", 2);
+					options & ~PHP_JSON_NUMERIC_CHECK, encoder) == FAILURE) {
+				if (!(options & PHP_JSON_PARTIAL_OUTPUT_ON_ERROR)) {
+					PHP_JSON_HASH_UNPROTECT_RECURSION(obj);
+					return FAILURE;
+				}
+				if (buf->s) {
+					ZSTR_LEN(buf->s) -= 4;
+					smart_str_appendl(buf, "\"\"", 2);
+				}
 			}
 
 			smart_str_appendc(buf, ':');
@@ -302,11 +306,17 @@ static zend_result php_json_encode_array(smart_str *buf, zval *val, int options,
 					php_json_pretty_print_indent(buf, options, encoder);
 
 					if (php_json_escape_string(buf, ZSTR_VAL(key), ZSTR_LEN(key),
-								options & ~PHP_JSON_NUMERIC_CHECK, encoder) == FAILURE &&
-							(options & PHP_JSON_PARTIAL_OUTPUT_ON_ERROR) &&
-							buf->s) {
-						ZSTR_LEN(buf->s) -= 4;
-						smart_str_appendl(buf, "\"\"", 2);
+								options & ~PHP_JSON_NUMERIC_CHECK, encoder) == FAILURE) {
+						if (!(options & PHP_JSON_PARTIAL_OUTPUT_ON_ERROR)) {
+							PHP_JSON_HASH_UNPROTECT_RECURSION(recursion_rc);
+							zend_release_properties(prop_ht);
+							zval_ptr_dtor(&tmp);
+							return FAILURE;
+						}
+						if (buf->s) {
+							ZSTR_LEN(buf->s) -= 4;
+							smart_str_appendl(buf, "\"\"", 2);
+						}
 					}
 				} else {
 					if (need_comma) {
diff --git a/ext/json/tests/json_encode_invalid_key_aborts.phpt b/ext/json/tests/json_encode_invalid_key_aborts.phpt
new file mode 100644
index 000000000000..76afc5be43f3
--- /dev/null
+++ b/ext/json/tests/json_encode_invalid_key_aborts.phpt
@@ -0,0 +1,55 @@
+--TEST--
+json_encode() stops encoding after an object or array key fails to encode
+--FILE--
+<?php
+
+class Value implements JsonSerializable
+{
+    public function jsonSerialize(): mixed
+    {
+        echo "jsonSerialize() called\n";
+        return 1;
+    }
+}
+
+eval('class Declared { public $' . "\xff" . ' = 1; public $next; }');
+
+$dynamic = new stdClass;
+$dynamic->{"\xff"} = 1;
+$dynamic->next = new Value;
+
+$declared = new Declared;
+$declared->next = new Value;
+
+$cases = [
+    'array' => ["\xff" => 1, 'next' => new Value],
+    'array, later NAN' => ["\xff" => 1, 'next' => NAN],
+    'dynamic property' => $dynamic,
+    'declared property' => $declared,
+];
+
+foreach ($cases as $name => $value) {
+    echo "$name:\n";
+    var_dump(json_encode($value), json_last_error_msg());
+}
+
+echo "partial output:\n";
+var_dump(json_encode(["\xff" => 1, 'next' => 2], JSON_PARTIAL_OUTPUT_ON_ERROR), json_last_error_msg());
+
+?>
+--EXPECT--
+array:
+bool(false)
+string(56) "Malformed UTF-8 characters, possibly incorrectly encoded"
+array, later NAN:
+bool(false)
+string(56) "Malformed UTF-8 characters, possibly incorrectly encoded"
+dynamic property:
+bool(false)
+string(56) "Malformed UTF-8 characters, possibly incorrectly encoded"
+declared property:
+bool(false)
+string(56) "Malformed UTF-8 characters, possibly incorrectly encoded"
+partial output:
+string(15) "{"":1,"next":2}"
+string(56) "Malformed UTF-8 characters, possibly incorrectly encoded"