diff --git a/PC/_winreg.c b/PC/_winreg.c
index f0f8df33107bea..3b887e075334be 100644
--- a/PC/_winreg.c
+++ b/PC/_winreg.c
@@ -727,7 +727,7 @@ fixupMultiSZ(char **str, char *data, int len)
     Q = data + len;
     for (P = data, i = 0; P < Q && *P != '\0'; P++, i++) {
         str[i] = P;
-        for(; *P != '\0'; P++)
+        for (; P < Q && *P != '\0'; P++)
             ;
     }
 }