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 00000000000000..a02631f2da2f9b
--- /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 bb14a1e78c5ad3..9643426fa74c88 100644
--- a/Parser/pegen.c
+++ b/Parser/pegen.c
@@ -1083,6 +1083,7 @@ _PyPegen_set_syntax_error_metadata(Parser *p) {
     );
     if (!metadata) {
         PyErr_Clear();
+        PyErr_SetRaisedException(exc);
         return;
     }
     PySyntaxErrorObject *syntax_error = (PySyntaxErrorObject *)exc;