Issue #23055: Fixed read-past-the-end error in PyUnicode_FromFormatV.

diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 1d1d5313c34892cb3d9b9d74830ec9815ff7450b..090cc1f4b13a830a4c86313516aeaa4321ed797e 100644 (file)
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -762,6 +762,8 @@ PyUnicode_FromFormatV(const char *format, va_list vargs)
              f++;
              while (*f && *f != '%' && !Py_ISALPHA((unsigned)*f))
                  f++;
+             if (!*f)
+                 break;
              if (*f == 's' || *f=='S' || *f=='R' || *f=='A' || *f=='V')
                  ++callcount;
          }