diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
index ffc59dab9..2ae5ca33d 100644
--- a/Lib/test/test_bytes.py
+++ b/Lib/test/test_bytes.py
@@ -1393,7 +1393,6 @@ class ByteArrayTest(BaseBytesTest, unittest.TestCase):
             except OSError:
                 pass
 
-    @unittest.skip("TODO: RUSTPYTHON; segfault")
     def test_mod_concurrent_mutation(self):
         # Prevent crash in __mod__ when formatting mutates the bytearray.
         # Regression test for https://github.com/python/cpython/issues/142557.
diff --git a/crates/vm/src/builtins/bytearray.rs b/crates/vm/src/builtins/bytearray.rs
index ac7e071f5..8ad76aefc 100644
--- a/crates/vm/src/builtins/bytearray.rs
+++ b/crates/vm/src/builtins/bytearray.rs
@@ -454,7 +454,9 @@ impl PyByteArray {
 
     fn __mod__(&self, values: PyObjectRef, vm: &VirtualMachine) -> PyResult<Self> {
         // Formatting calls the values' conversion methods, which can reach
-        // this bytearray, so the format is taken by value.
+        // this bytearray, so the format is taken by value. It also stays
+        // exported until formatting ends, so resizing it raises BufferError.
+        let _export = self.begin_export();
         let format = self.inner().clone();
         let formatted = format.cformat(values, vm)?;
         Ok(formatted.into())