diff --git a/zion/memory/constants.h b/zion/memory/constants.h
index 2c17ba3..7b619b2 100644
--- a/zion/memory/constants.h
+++ b/zion/memory/constants.h
@@ -25,3 +25,5 @@ const uint64_t kKernelStackOffset = 4 * kPageSize;
 const uint64_t kUserStackMin = 0x00007FF0'00000000;
 const uint64_t kUserStackMax = 0x00008000'00000000;
 const uint64_t kUserStackSize = MiB;
+
+const uint64_t kUserSpaceMax = 0x00008000'00000000;
diff --git a/zion/object/process.cpp b/zion/object/process.cpp
index 55e73ed..f0c7e86 100644
--- a/zion/object/process.cpp
+++ b/zion/object/process.cpp
@@ -101,7 +101,9 @@ void Process::Cleanup() {
   // 2. Release all capabailities.
   caps_.ReleaseAll();
 
-  // 3. Unmap all user memory. TODO
+  // 3. Unmap all user memory.
+  PANIC_ON_ERR(vmas_->FreeAddressRange(0, kUserSpaceMax),
+               "Failed to cleanup userspace mappings in process exit.");
 
   // 4. Release paging structures. TODO
   state_ = FINISHED;