diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 32ba3478..1212956e 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -14,7 +14,7 @@ jobs:
   fmt:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - run: rustup update
       - run: rustup component add rustfmt
       - run: cargo fmt -- --check
@@ -22,7 +22,7 @@ jobs:
   clippy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - run: rustup update
       - run: rustup component add clippy
       - run: cargo clippy --all --all-targets --all-features
@@ -30,7 +30,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2.3.4
       with:
         submodules: true
     - run: rustup update
@@ -42,7 +42,7 @@ jobs:
   js:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - run: rustup update
       - run: cargo install wasm-pack
       - run: npm install
@@ -53,7 +53,7 @@ jobs:
   python:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - run: rustup update
       - uses: actions/setup-python@v2
         with:
@@ -76,7 +76,7 @@ jobs:
       matrix:
         os: [ ubuntu-latest, macos-latest, windows-latest ]
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - uses: actions/setup-python@v2
         with:
           python-version: 3.6
diff --git a/.github/workflows/doc.yml b/.github/workflows/doc.yml
index ac4d9ff5..7eff7538 100644
--- a/.github/workflows/doc.yml
+++ b/.github/workflows/doc.yml
@@ -9,7 +9,7 @@ jobs:
   python:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - run: rustup update
       - uses: actions/setup-python@v2
         with:
@@ -22,7 +22,7 @@ jobs:
         working-directory: ./python/docs
       - run: source ../venv/bin/activate && sphinx-build -M html . build
         working-directory: ./python/docs
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
         with:
           repository: oxigraph/oxigraph.github.io
           path: website
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index fabfdb58..ad4a09cc 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -8,7 +8,7 @@ jobs:
   push_server_to_docker_registry:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - uses: docker/metadata-action@v3
         id: docker_meta
         with:
@@ -29,7 +29,7 @@ jobs:
   push_wikibase_to_docker_registry:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - uses: docker/metadata-action@v3
         id: docker_meta
         with:
@@ -50,7 +50,7 @@ jobs:
   publish_lib_crate:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - run: rustup update
       - run: cargo login $CRATES_IO_TOKEN
         env:
@@ -61,7 +61,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: publish_lib_crate
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - run: rustup update
       - run: cargo login $CRATES_IO_TOKEN
         env:
@@ -72,7 +72,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: publish_lib_crate
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - run: rustup update
       - run: cargo login $CRATES_IO_TOKEN
         env:
@@ -83,7 +83,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: publish_lib_crate
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - run: sed -i 's/path="..\/lib", //g' python/Cargo.toml
       - run: docker run --rm -v $(pwd):/io konstin2/maturin:v0.9.4 publish -u __token__ -p ${{ secrets.PYPI_PASSWORD }}
         working-directory: ./python
@@ -94,7 +94,7 @@ jobs:
       matrix:
         os: [ macos-latest, windows-latest ]
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - uses: actions/setup-python@v2
         with:
           python-version: 3.6
@@ -104,7 +104,7 @@ jobs:
   publish_npm:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - uses: actions/setup-node@v2
         with:
           node-version: 14
@@ -122,7 +122,7 @@ jobs:
   publish_python_doc:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - run: rustup update
       - uses: actions/setup-python@v2
         with:
@@ -135,7 +135,7 @@ jobs:
         working-directory: ./python/docs
       - run: source ../venv/bin/activate && sphinx-build -M html . build
         working-directory: ./python/docs
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
         with:
           repository: oxigraph/oxigraph.github.io
           path: website
@@ -154,7 +154,7 @@ jobs:
   publish_homebrew:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
         with:
           repository: oxigraph/homebrew-oxigraph
           token: ${{ secrets.FULL_ACCESS_TOKEN }}