diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-10-19-19-33-35.gh-issue-159739.1fc3af.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-10-19-19-33-35.gh-issue-159739.1fc3af.rst
new file mode 100644
index 000000000000000..a02631f2da2f9b2
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-10-19-19-33-35.gh-issue-159739.1fc3af.rst
@@ -0,0 +1,2 @@
+Preserve the original :exc:`SyntaxError` if allocating optional error metadata
+fails.
diff --git a/Parser/pegen.c b/Parser/pegen.c
index 1dc039fccfa2491..fb8d7977ec0427b 100644
--- a/Parser/pegen.c
+++ b/Parser/pegen.c
@@ -933,8 +933,8 @@ _PyPegen_set_syntax_error_metadata(Parser *p) {
         the_source // N gives ownership to metadata
     );
     if (!metadata) {
-        Py_DECREF(the_source);
         PyErr_Clear();
+        PyErr_SetRaisedException(exc);
         return;
     }
     PySyntaxErrorObject *syntax_error = (PySyntaxErrorObject *)exc;