diff --git a/.github/workflows/csharp.yml b/.github/workflows/csharp.yml
index d9e6cc461..8e4846460 100644
--- a/.github/workflows/csharp.yml
+++ b/.github/workflows/csharp.yml
@@ -23,11 +23,17 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-26.04, macos-latest]
+    env:
+      RUSTUP_TOOLCHAIN: 1.85.0
     steps:
       - name: Checkout
         uses: actions/checkout@v6
+      - name: "Install Rust 1.85.0"
+        uses: dtolnay/rust-toolchain@1.85.0
       - name: "Use cache"
         uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: msrv-workspace
       - name: Set up nix
         uses: ./.github/actions/setup-nix
       - name: "Build and test"
diff --git a/.github/workflows/dart.yml b/.github/workflows/dart.yml
index bae18ae95..d8dc44124 100644
--- a/.github/workflows/dart.yml
+++ b/.github/workflows/dart.yml
@@ -23,11 +23,17 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-26.04, macos-latest]
+    env:
+      RUSTUP_TOOLCHAIN: 1.85.0
     steps:
       - name: Checkout
         uses: actions/checkout@v6
+      - name: "Install Rust 1.85.0"
+        uses: dtolnay/rust-toolchain@1.85.0
       - name: "Use cache"
         uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: msrv-workspace
       - name: Set up nix
         uses: ./.github/actions/setup-nix
       - name: "Build and test"
diff --git a/.github/workflows/javascript.yml b/.github/workflows/javascript.yml
index 168eb5f4b..845fcbe9c 100644
--- a/.github/workflows/javascript.yml
+++ b/.github/workflows/javascript.yml
@@ -23,11 +23,17 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-26.04, macos-latest]
+    env:
+      RUSTUP_TOOLCHAIN: 1.85.0
     steps:
       - name: Checkout
         uses: actions/checkout@v6
+      - name: "Install Rust 1.85.0"
+        uses: dtolnay/rust-toolchain@1.85.0
       - name: "Use cache"
         uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: msrv-workspace
       - name: Set up nix
         uses: ./.github/actions/setup-nix
       - name: "Build and test"
diff --git a/.github/workflows/python.yml b/.github/workflows/python.yml
index ff87b9d9d..b84941caf 100644
--- a/.github/workflows/python.yml
+++ b/.github/workflows/python.yml
@@ -23,11 +23,17 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-26.04, macos-latest]
+    env:
+      RUSTUP_TOOLCHAIN: 1.85.0
     steps:
       - name: Checkout
         uses: actions/checkout@v6
+      - name: "Install Rust 1.85.0"
+        uses: dtolnay/rust-toolchain@1.85.0
       - name: "Use cache"
         uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: msrv-workspace
       - name: Set up nix
         uses: ./.github/actions/setup-nix
       - name: "Build and test"
diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 010eb9afe..47504f28a 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -35,6 +35,8 @@ jobs:
           echo "$(nix build .#nginx-with-stream --print-out-paths --no-link)/bin" >> $GITHUB_PATH
       - name: "Use cache"
         uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: ${{ matrix.rust == 'stable' && 'stable-workspace' || matrix.rust == '1.85.0' && 'msrv-workspace' || '' }}
       - name: Run tests
         run: RUST_LOG=debug bash contrib/test.sh