diff --git a/lldb/source/Utility/UUID.cpp b/lldb/source/Utility/UUID.cpp
--- a/lldb/source/Utility/UUID.cpp
+++ b/lldb/source/Utility/UUID.cpp
@@ -64,7 +64,7 @@
                                 llvm::SmallVectorImpl<uint8_t> &uuid_bytes,
                                 uint32_t num_uuid_bytes) {
   uuid_bytes.clear();
-  while (!p.empty()) {
+  while (p.size() > 1) {
     if (isxdigit(p[0]) && isxdigit(p[1])) {
       int hi_nibble = xdigit_to_int(p[0]);
       int lo_nibble = xdigit_to_int(p[1]);
diff --git a/lldb/unittests/Utility/UUIDTest.cpp b/lldb/unittests/Utility/UUIDTest.cpp
--- a/lldb/unittests/Utility/UUIDTest.cpp
+++ b/lldb/unittests/Utility/UUIDTest.cpp
@@ -69,6 +69,7 @@
 
   EXPECT_EQ(0u, u.SetFromStringRef("40-41-42-43-4445464748494a4b4c4d4e4f", 20));
   EXPECT_EQ(0u, u.SetFromStringRef("40xxxxx"));
+  EXPECT_EQ(0u, u.SetFromStringRef("404142434445464748494a4b4c4d4e4"));
   EXPECT_EQ(0u, u.SetFromStringRef(""));
   EXPECT_EQ(UUID::fromData("@ABCDEFGHIJKLMNOPQRS", 20), u)
       << "uuid was changed by failed parse calls";