diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 60466f0c..af9e0c3a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -99,7 +99,7 @@ jobs:
           }
 
       - name: Install Rust ${{ matrix.rust }}
-        uses: dtolnay/rust-toolchain@master
+        uses: dtolnay/rust-toolchain@3c5f7ea28cd621ae0bf5283f0e981fb97b8a7af9 # master
         with:
           toolchain: ${{ matrix.rust }}
 
@@ -135,7 +135,7 @@ jobs:
         run: rm -f rust-toolchain.toml
 
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@stable
+        uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable
         with:
           targets: armv7-linux-androideabi, aarch64-linux-android