diff --git a/libc/malloc_debug/MapData.cpp b/libc/malloc_debug/MapData.cpp
index 8e9c806..d57017e 100644
--- a/libc/malloc_debug/MapData.cpp
+++ b/libc/malloc_debug/MapData.cpp
@@ -44,7 +44,7 @@
   uintptr_t start;
   uintptr_t end;
   uintptr_t offset;
-  char permissions[4];
+  char permissions[5];
   int name_pos;
   if (sscanf(line, "%" PRIxPTR "-%" PRIxPTR " %4s %" PRIxPTR " %*x:%*x %*d %n", &start,
              &end, permissions, &offset, &name_pos) < 2) {