diff --git a/ext/dom/html_document.c b/ext/dom/html_document.c
index ed7454dd89d43..240fa71a0cca7 100644
--- a/ext/dom/html_document.c
+++ b/ext/dom/html_document.c
@@ -880,6 +880,13 @@ PHP_METHOD(Dom_HTMLDocument, createFromString)
if (!result) {
goto fail_oom;
}
+
+ /* In the string case we have a single buffer that acts as a sliding window.
+ * The `current_input_characters` field starts pointing at the start of the buffer, but needs to slide along the
+ * sliding window as well. */
+ if (application_data.current_input_characters) {
+ application_data.current_input_characters += chunk_size;
+ }
}
if (!dom_parse_decode_encode_finish(&ctx, document, parser, &decoding_encoding_ctx, &tokenizer_error_offset, &tree_error_offset)) {
diff --git a/ext/dom/tests/modern/html/parser/gh17486.phpt b/ext/dom/tests/modern/html/parser/gh17486.phpt
new file mode 100644
index 0000000000000..4d7ddee7dde96
--- /dev/null
+++ b/ext/dom/tests/modern/html/parser/gh17486.phpt
@@ -0,0 +1,39 @@
+--TEST--
+GH-17486 (Incorrect error line numbers reported in Dom\HTMLDocument::createFromString)
+--EXTENSIONS--
+dom
+--INI--
+error_reporting=E_ALL
+--CREDITS--
+xPaw
+--FILE--
+
+
+
+
+
�
+
+
+HTML;
+
+\Dom\HTMLDocument::createFromString($html);
+
+file_put_contents(__DIR__ . '/gh17486.tmp', $html);
+\Dom\HTMLDocument::createFromFile(__DIR__ . '/gh17486.tmp');
+
+?>
+--CLEAN--
+
+--EXPECTF--
+Warning: Dom\HTMLDocument::createFromString(): tokenizer error null-character-reference in Entity, line: 7, column: 9 in %s on line %d
+
+Warning: Dom\HTMLDocument::createFromFile(): tokenizer error null-character-reference in %s line: 7, column: 9 in %s on line %d