diff --git a/.github/workflows/boulder-ci.yml b/.github/workflows/boulder-ci.yml
index ec99a0e4516..90d13c17ba1 100644
--- a/.github/workflows/boulder-ci.yml
+++ b/.github/workflows/boulder-ci.yml
@@ -71,7 +71,7 @@ jobs:
     # Sequence of tasks that will be executed as part of the job.
     steps:
       # Checks out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 
@@ -108,7 +108,7 @@ jobs:
 
     steps:
       # Checks out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 
@@ -133,7 +133,7 @@ jobs:
 
     steps:
       # Checks out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 
diff --git a/.github/workflows/check-iana-registries.yml b/.github/workflows/check-iana-registries.yml
index 4e78841633f..7506354c0c0 100644
--- a/.github/workflows/check-iana-registries.yml
+++ b/.github/workflows/check-iana-registries.yml
@@ -15,8 +15,9 @@ jobs:
 
     steps:
       - name: Checkout iana/data from main branch
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
+          persist-credentials: false
           sparse-checkout: iana/data
 
       # If the branch already exists, this will fail, which will remind us about
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 3d37465950b..216650cdafd 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -18,7 +18,9 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
+        with:
+          persist-credentials: false
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v4
       - name: Autobuild
diff --git a/.github/workflows/cps-review.yml b/.github/workflows/cps-review.yml
index c416fca66b8..6aa021eb411 100644
--- a/.github/workflows/cps-review.yml
+++ b/.github/workflows/cps-review.yml
@@ -18,14 +18,17 @@ jobs:
           go-version: "stable"
 
       - name: Checkout Upstream
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
+          persist-credentials: false
           ref: ${{ github.event.pull_request.base.ref }}
       - name: Get Current Flags
         run: go run ./test/list-features/list-features.go | sort >| /tmp/currflags.txt
 
       - name: Checkout PR
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
+        with:
+          persist-credentials: false
       - name: Get PR Flags
         run: go run ./test/list-features/list-features.go | sort >| /tmp/prflags.txt
 
diff --git a/.github/workflows/merged-to-main-or-release-branch.yml b/.github/workflows/merged-to-main-or-release-branch.yml
index a1afad4f904..aacf553d701 100644
--- a/.github/workflows/merged-to-main-or-release-branch.yml
+++ b/.github/workflows/merged-to-main-or-release-branch.yml
@@ -14,6 +14,6 @@ jobs:
     name: Merged to main (or hotfix)
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index dbfa6bec613..ee87484f739 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -15,7 +15,7 @@ jobs:
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
           fetch-depth: '0' # Needed for verify-release-ancestry.sh to see origin/main
@@ -41,7 +41,7 @@ jobs:
       contents: write
       packages: write
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
           fetch-depth: '0' # Needed for verify-release-ancestry.sh to see origin/main
@@ -89,7 +89,7 @@ jobs:
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 
diff --git a/.github/workflows/try-release.yml b/.github/workflows/try-release.yml
index b0c734174e8..0b5a371f1f3 100644
--- a/.github/workflows/try-release.yml
+++ b/.github/workflows/try-release.yml
@@ -23,7 +23,7 @@ jobs:
           - "1.25.5"
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false