diff --git a/libutils/String8.cpp b/libutils/String8.cpp
index 28be60f..69313ea 100644
--- a/libutils/String8.cpp
+++ b/libutils/String8.cpp
@@ -79,6 +79,9 @@
 static char* allocFromUTF8(const char* in, size_t len)
 {
     if (len > 0) {
+        if (len == SIZE_MAX) {
+            return NULL;
+        }
         SharedBuffer* buf = SharedBuffer::alloc(len+1);
         ALOG_ASSERT(buf, "Unable to allocate shared buffer");
         if (buf) {