diff --git a/dmoj/executors/base_executor.py b/dmoj/executors/base_executor.py
index b7eeeecef..f099bcb38 100644
--- a/dmoj/executors/base_executor.py
+++ b/dmoj/executors/base_executor.py
@@ -135,6 +135,7 @@ class BaseExecutor(metaclass=ExecutorMeta):
     def __init__(
         self,
         problem_id: str,
+        storage_namespace: Optional[str],
         source_code: bytes,
         dest_dir: Optional[str] = None,
         hints: Optional[List[str]] = None,
@@ -144,6 +145,7 @@ def __init__(
         self._tempdir = dest_dir or env.tempdir
         self._dir = None
         self.problem = problem_id
+        self.storage_namespace = '' if storage_namespace is None else storage_namespace
         self.source = source_code
         self._hints = hints or []
         self.unbuffered = unbuffered
diff --git a/dmoj/executors/c_like_executor.py b/dmoj/executors/c_like_executor.py
index 48b984514..02dcb5b12 100644
--- a/dmoj/executors/c_like_executor.py
+++ b/dmoj/executors/c_like_executor.py
@@ -51,7 +51,10 @@ def get_binary_cache_key(self) -> bytes:
         command = self.get_command()
         assert command is not None
         key_components = (
-            [self.problem, command, self.get_march_flag()] + self.get_defines() + self.get_flags() + self.get_ldflags()
+            [self.storage_namespace, self.problem, command, self.get_march_flag()]
+            + self.get_defines()
+            + self.get_flags()
+            + self.get_ldflags()
         )
         return utf8bytes(''.join(key_components)) + b''.join(self.source_dict.values())
 
diff --git a/dmoj/executors/compiled_executor.py b/dmoj/executors/compiled_executor.py
index b5bf61d75..9babe04bf 100644
--- a/dmoj/executors/compiled_executor.py
+++ b/dmoj/executors/compiled_executor.py
@@ -213,7 +213,7 @@ def handle_compile_error(self, output: bytes) -> None:
         raise CompileError(output)
 
     def get_binary_cache_key(self) -> bytes:
-        return utf8bytes(self.problem) + self.source
+        return utf8bytes(self.storage_namespace) + utf8bytes(self.problem) + self.source
 
     def compile(self) -> str:
         process = self.create_compile_process(self.get_compile_args())
diff --git a/dmoj/graders/communication.py b/dmoj/graders/communication.py
index 360640a84..7f820dffa 100644
--- a/dmoj/graders/communication.py
+++ b/dmoj/graders/communication.py
@@ -203,7 +203,11 @@ def _generate_binary(self) -> BaseExecutor:
             aux_sources[signature_data['header']] = header
             entry = entry_point
             return executors[self.language].Executor(
-                self.problem.id, entry, aux_sources=aux_sources, defines=['-DSIGNATURE_GRADER']
+                self.problem.id,
+                self.problem.storage_namespace,
+                entry,
+                aux_sources=aux_sources,
+                defines=['-DSIGNATURE_GRADER'],
             )
         elif self.language in java_siggraders:
             aux_sources = {}
@@ -218,7 +222,9 @@ def _generate_binary(self) -> BaseExecutor:
                 entry = self.source
                 aux_sources[self.problem.id + '_lib'] = entry_point
 
-            return executors[self.language].Executor(self.problem.id, entry, aux_sources=aux_sources)
+            return executors[self.language].Executor(
+                self.problem.id, self.problem.storage_namespace, entry, aux_sources=aux_sources
+            )
         else:
             raise InternalError('no valid runtime for signature grading %s found' % self.language)
 
diff --git a/dmoj/graders/signature.py b/dmoj/graders/signature.py
index 8584f244b..b36f67746 100644
--- a/dmoj/graders/signature.py
+++ b/dmoj/graders/signature.py
@@ -28,7 +28,11 @@ def _generate_binary(self) -> BaseExecutor:
             aux_sources[handler_data['header']] = header
             entry = entry_point
             return executors[self.language].Executor(
-                self.problem.id, entry, aux_sources=aux_sources, defines=['-DSIGNATURE_GRADER']
+                self.problem.id,
+                self.problem.storage_namespace,
+                entry,
+                aux_sources=aux_sources,
+                defines=['-DSIGNATURE_GRADER'],
             )
         elif self.language in java_siggraders:
             aux_sources = {}
@@ -43,6 +47,8 @@ def _generate_binary(self) -> BaseExecutor:
                 entry = self.source
                 aux_sources[self.problem.id + '_lib'] = entry_point
 
-            return executors[self.language].Executor(self.problem.id, entry, aux_sources=aux_sources)
+            return executors[self.language].Executor(
+                self.problem.id, self.problem.storage_namespace, entry, aux_sources=aux_sources
+            )
         else:
             raise InternalError('no valid runtime for signature grading %s found' % self.language)
diff --git a/dmoj/graders/standard.py b/dmoj/graders/standard.py
index 42cd560aa..d088b5d58 100644
--- a/dmoj/graders/standard.py
+++ b/dmoj/graders/standard.py
@@ -109,6 +109,7 @@ def _interact_with_process(self, case: TestCase, result: Result, input: bytes) -
     def _generate_binary(self) -> BaseExecutor:
         return executors[self.language].Executor(
             self.problem.id,
+            self.problem.storage_namespace,
             self.source,
             hints=self.problem.config.hints or [],
             unbuffered=self.problem.config.unbuffered,