diff --git a/.github/scripts/test.mjs b/.github/scripts/test.mjs
index 50385b4..5a1cc09 100644
--- a/.github/scripts/test.mjs
+++ b/.github/scripts/test.mjs
@@ -4,6 +4,7 @@ import fs from 'fs';
 
 const { default: initialize } = await import('./initialize-request.mjs');
 const { default: complete } = await import('./approve-or-deny-request.mjs');
+const { default: validateRequest } = await import('./validate-request.mjs');
 
 import nock from 'nock';
 nock.disableNetConnect();
@@ -65,6 +66,59 @@ test.after.each(() => {
     // nothing to do here
 });
 
+test("Validate GitHub owner and repository names", function () {
+    const validRequests = [
+        { owner: "a", repo: "a" },
+        { owner: "a-b", repo: ".github" },
+        { owner: "a".repeat(39), repo: "a".repeat(100) },
+        { owner: "GitHub", repo: "repo_name-1.0" }
+    ];
+
+    for (const request of validRequests) {
+        assert.equal(validateRequest(JSON.stringify(request)), request);
+    }
+});
+
+test("Reject invalid GitHub owner names", function () {
+    const invalidOwners = [
+        "",
+        "-owner",
+        "owner-",
+        "owner--name",
+        "owner_name",
+        "owner/name",
+        "owner name",
+        "a".repeat(40)
+    ];
+
+    for (const owner of invalidOwners) {
+        assert.throws(() => validateRequest({ owner, repo: "repo" }), /Owner must/);
+    }
+});
+
+test("Reject invalid GitHub repository names", function () {
+    const invalidRepositories = [
+        "",
+        "repo/name",
+        "repo name",
+        "repo$name",
+        "répo",
+        "a".repeat(101)
+    ];
+
+    for (const repo of invalidRepositories) {
+        assert.throws(() => validateRequest({ owner: "owner", repo }), /Repository must/);
+    }
+});
+
+test("Reject malformed request payloads", function () {
+    assert.throws(() => validateRequest("not json"), /valid JSON/);
+    assert.throws(() => validateRequest(null), /JSON object/);
+    assert.throws(() => validateRequest([]), /JSON object/);
+    assert.throws(() => validateRequest({ owner: "owner" }), /Repository must/);
+    assert.throws(() => validateRequest({ repo: "repo" }), /Owner must/);
+});
+
 // Fail the workflow because the repo already exists
 test("Fail the workflow because the repo already exists", async function () {
     let mock = nock("https://github.robandpdx.demo-stack.com/api/v3");
diff --git a/.github/scripts/validate-request.mjs b/.github/scripts/validate-request.mjs
new file mode 100644
index 0000000..db9a238
--- /dev/null
+++ b/.github/scripts/validate-request.mjs
@@ -0,0 +1,33 @@
+const OWNER_PATTERN = /^[A-Za-z0-9]+(?:-[A-Za-z0-9]+)*$/;
+const REPOSITORY_PATTERN = /^[A-Za-z0-9._-]+$/;
+
+export default function validateRequest(payload) {
+    let request;
+
+    try {
+        request = typeof payload === 'string' ? JSON.parse(payload) : payload;
+    } catch {
+        throw new Error('Request payload must be valid JSON');
+    }
+
+    if (!request || typeof request !== 'object' || Array.isArray(request)) {
+        throw new Error('Request payload must be a JSON object');
+    }
+
+    validateOwner(request.owner);
+    validateRepository(request.repo);
+
+    return request;
+}
+
+function validateOwner(owner) {
+    if (typeof owner !== 'string' || owner.length < 1 || owner.length > 39 || !OWNER_PATTERN.test(owner)) {
+        throw new Error('Owner must be 1-39 ASCII letters, digits, or single hyphens, and cannot begin or end with a hyphen');
+    }
+}
+
+function validateRepository(repo) {
+    if (typeof repo !== 'string' || repo.length < 1 || repo.length > 100 || !REPOSITORY_PATTERN.test(repo)) {
+        throw new Error('Repository must be 1-100 ASCII letters, digits, periods, hyphens, or underscores');
+    }
+}
\ No newline at end of file
diff --git a/.github/workflows/approve-or-deny-request.yml b/.github/workflows/approve-or-deny-request.yml
index b1d78cb..c9ed806 100644
--- a/.github/workflows/approve-or-deny-request.yml
+++ b/.github/workflows/approve-or-deny-request.yml
@@ -15,13 +15,25 @@ jobs:
       payload: ${{ steps.issue_body_parser_request.outputs.payload }}
     steps:
       - name: Get JSON Data out of Issue Request
-        uses: peter-murray/issue-body-parser-action@v3
+        uses: peter-murray/issue-body-parser-action@6f0770bae810c272cbdccf6f817b0759a9d82647 # v3
         id: issue_body_parser_request
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           issue_id: ${{ github.event.issue.number }}
           payload_marker: request
           fail_on_missing: false
+      - name: Check out request validator
+        if: steps.issue_body_parser_request.outputs.payload != 'NOT_FOUND'
+        uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+      - name: Validate requested repository
+        if: steps.issue_body_parser_request.outputs.payload != 'NOT_FOUND'
+        uses: actions/github-script@f28e40c7f34bde8b3046d885e986cb6290c5673b # v7
+        env:
+          REQUEST_PAYLOAD: ${{ steps.issue_body_parser_request.outputs.payload }}
+        with:
+          script: |
+            const { default: validateRequest } = await import('${{ github.workspace }}/.github/scripts/validate-request.mjs');
+            validateRequest(process.env.REQUEST_PAYLOAD);
   approve-or-deny-request:
     runs-on: self-hosted
     needs: parse-issue
@@ -34,18 +46,18 @@ jobs:
         REPO: ${{ fromJson(needs.parse-issue.outputs.payload).repo }}
         REQUEST_VERSION: ${{ fromJson(needs.parse-issue.outputs.payload).version }}
       run: |
-        if [ $REQUEST_VERSION == 'latest' ]; then
+        if [ "$REQUEST_VERSION" = 'latest' ]; then
           echo "Finding latest release of $OWNER/$REPO..."
-          export VERSION=`curl https://api.github.com/repos/$OWNER/$REPO/releases/latest | jq -r .name`
+          VERSION=$(curl "https://api.github.com/repos/$OWNER/$REPO/releases/latest" | jq -r .name)
         else
-          export VERSION=$REQUEST_VERSION
+          VERSION="$REQUEST_VERSION"
         fi
         echo "VERSION: $VERSION"
-        echo "version=$VERSION" >> $GITHUB_OUTPUT
+        echo "version=$VERSION" >> "$GITHUB_OUTPUT"
     - name: Check out scripts
-      uses: actions/checkout@v4
+      uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
     - name: Setup Node
-      uses: actions/setup-node@v4
+      uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
       with:
         node-version: '20'
         check-latest: true
@@ -54,7 +66,7 @@ jobs:
         cd .github/scripts
         npm install
     - name: Approve or deny request
-      uses: actions/github-script@v7
+      uses: actions/github-script@f28e40c7f34bde8b3046d885e986cb6290c5673b # v7
       env:
         VERSION: ${{ steps.get_version.outputs.version }}
         REPO: ${{ fromJson(needs.parse-issue.outputs.payload).repo }}
diff --git a/.github/workflows/initialize-request.yml b/.github/workflows/initialize-request.yml
index b8e648b..65f2748 100644
--- a/.github/workflows/initialize-request.yml
+++ b/.github/workflows/initialize-request.yml
@@ -15,13 +15,25 @@ jobs:
       payload: ${{ steps.issue_body_parser_request.outputs.payload }}
     steps:
       - name: Get JSON Data out of Issue Request
-        uses: peter-murray/issue-body-parser-action@v3
+        uses: peter-murray/issue-body-parser-action@6f0770bae810c272cbdccf6f817b0759a9d82647 # v3
         id: issue_body_parser_request
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           issue_id: ${{ github.event.issue.number }}
           payload_marker: request
           fail_on_missing: false
+      - name: Check out request validator
+        if: steps.issue_body_parser_request.outputs.payload != 'NOT_FOUND'
+        uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+      - name: Validate requested repository
+        if: steps.issue_body_parser_request.outputs.payload != 'NOT_FOUND'
+        uses: actions/github-script@f28e40c7f34bde8b3046d885e986cb6290c5673b # v7
+        env:
+          REQUEST_PAYLOAD: ${{ steps.issue_body_parser_request.outputs.payload }}
+        with:
+          script: |
+            const { default: validateRequest } = await import('${{ github.workspace }}/.github/scripts/validate-request.mjs');
+            validateRequest(process.env.REQUEST_PAYLOAD);
   initialize-request:
     runs-on: self-hosted
     needs: parse-issue
@@ -34,22 +46,22 @@ jobs:
         REPO: ${{ fromJson(needs.parse-issue.outputs.payload).repo }}
         REQUEST_VERSION: ${{ fromJson(needs.parse-issue.outputs.payload).version }}
       run: |
-        if [ $REQUEST_VERSION == 'latest' ]; then
+        if [ "$REQUEST_VERSION" = 'latest' ]; then
           echo "Finding latest release of $OWNER/$REPO..."
-          export VERSION=`curl https://api.github.com/repos/$OWNER/$REPO/releases/latest | jq -r .name`
+          VERSION=$(curl "https://api.github.com/repos/$OWNER/$REPO/releases/latest" | jq -r .name)
           if [ "$VERSION" == "null" ]; then
             echo "No latest version found for $OWNER/$REPO"
             exit 1
           fi
         else
-          export VERSION=$REQUEST_VERSION
+          VERSION="$REQUEST_VERSION"
         fi
         echo "VERSION: $VERSION"
-        echo "version=$VERSION" >> $GITHUB_OUTPUT
+        echo "version=$VERSION" >> "$GITHUB_OUTPUT"
     - name: Check out scripts
-      uses: actions/checkout@v4
+      uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
     - name: Setup Node
-      uses: actions/setup-node@v4
+      uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
       with:
         node-version: '20'
         check-latest: true
@@ -58,7 +70,7 @@ jobs:
         cd .github/scripts
         npm install
     - name: Create the repo ${{ fromJson(needs.parse-issue.outputs.payload).repo }}_${{ steps.get_version.outputs.version }} on GitHub Enterprise Server
-      uses: actions/github-script@v7
+      uses: actions/github-script@f28e40c7f34bde8b3046d885e986cb6290c5673b # v7
       env:
         VERSION: ${{ steps.get_version.outputs.version }}
         OWNER: ${{ fromJson(needs.parse-issue.outputs.payload).owner }}
@@ -81,7 +93,7 @@ jobs:
         OWNER: ${{ fromJson(needs.parse-issue.outputs.payload).owner }}
         REPO: ${{ fromJson(needs.parse-issue.outputs.payload).repo }}
       run: |
-        git clone https://github.com/$OWNER/$REPO requested-action
+        git clone "https://github.com/$OWNER/$REPO" requested-action
     - name: Push requested action to private repo in $ACTIONS_APPROVED_ORG org on GitHub Enterprise Server
       env:
         REPO: ${{ fromJson(needs.parse-issue.outputs.payload).repo }}
diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index a8bd6f8..65f1c4a 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -17,8 +17,8 @@ jobs:
       working-directory: ./.github/scripts
 
     steps:
-    - uses: actions/checkout@v4
-    - uses: actions/setup-node@v4
+    - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 #v7.0.1
+    - uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 #v7.0.0
       with:
         node-version: '20'
         check-latest: true
@@ -28,8 +28,3 @@ jobs:
       working-directory: ${{ env.working-directory }}
     - run: npm test
       working-directory: ${{ env.working-directory }}
-    - uses: tintef/nyc-reporter-action@0.2.5
-      with:
-        GITHUB_TOKEN: ${{ github.token }}
-        SKIP_COVERAGE_FOLDER: true
-        WORKING_DIRECTORY: ${{ env.working-directory }}
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index c0e0d3e..0e30941 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -12,11 +12,12 @@ jobs:
     env:
       working-directory: ./.github/scripts
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 #v7.0.1
+      - uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 #v7.0.0
         with:
-          node-version: 20
-          cache: npm
+          node-version: '20'
+          check-latest: true
+          cache: 'npm'
           cache-dependency-path: ${{ env.working-directory }}/package-lock.json
       - run: npm ci
         working-directory: ${{ env.working-directory }}