diff --git a/PC/winreg.c b/PC/winreg.c
index e3801b257b0..96dd4ef059b 100644
--- a/PC/winreg.c
+++ b/PC/winreg.c
@@ -520,7 +520,7 @@ fixupMultiSZ(wchar_t **str, wchar_t *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++)
             ;
     }
 }