diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f6f4996d..4ca9c31a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.head_ref || github.ref_name }} 
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
       - uses: DeterminateSystems/nix-installer-action@main
       - uses: DeterminateSystems/magic-nix-cache-action@main
       - run: echo "${GITHUB_WORKSPACE}" >> $GITHUB_PATH
@@ -28,7 +29,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.head_ref || github.ref_name }} 
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
       - uses: DeterminateSystems/nix-installer-action@main
       - uses: DeterminateSystems/magic-nix-cache-action@main
       - run: echo "${GITHUB_WORKSPACE}" >> $GITHUB_PATH
@@ -40,7 +42,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.head_ref || github.ref_name }} 
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
       - uses: DeterminateSystems/nix-installer-action@main
       - uses: DeterminateSystems/magic-nix-cache-action@main
       - run: echo "${GITHUB_WORKSPACE}" >> $GITHUB_PATH
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 440ff2f5..7183830d 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -27,7 +27,8 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v3
         with:
-          ref: ${{ github.head_ref || github.ref_name }} 
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v2
diff --git a/.github/workflows/integration.yml b/.github/workflows/integration.yml
index ab65b707..0aa7b1b5 100644
--- a/.github/workflows/integration.yml
+++ b/.github/workflows/integration.yml
@@ -17,7 +17,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.head_ref || github.ref_name }} 
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
       - run: docker build -t "local-image" -f ${{ github.workspace }}/.github/dodona-image.dockerfile --network=host .
         name: Build Dodona Docker image
       - run: docker run -v ${{ github.workspace }}:/github/workspace -e TESTED_SOURCE=/github/workspace local-image
@@ -29,7 +30,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.head_ref || github.ref_name }} 
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
       - run: |
           echo "$JAVASCRIPT_EXERCISES_KEY" > private
           chmod 0600 private
@@ -50,7 +52,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.head_ref || github.ref_name }} 
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
       - uses: DeterminateSystems/nix-installer-action@main
       - uses: DeterminateSystems/magic-nix-cache-action@main
       - run: echo "${GITHUB_WORKSPACE}" >> $GITHUB_PATH