diff --git a/src/tools/miri/.github/workflows/ci.yml b/src/tools/miri/.github/workflows/ci.yml
index 2d26e33545c1..c05352f23d67 100644
--- a/src/tools/miri/.github/workflows/ci.yml
+++ b/src/tools/miri/.github/workflows/ci.yml
@@ -12,6 +12,9 @@ on:
   schedule:
     - cron: '5 15 * * *' # At 15:05 UTC every day.
 
+env:
+  CARGO_UNSTABLE_SPARSE_REGISTRY: 'true'
+
 jobs:
   build:
     runs-on: ${{ matrix.os }}