diff --git a/.github/workflows/eslint-code-scanning.yml b/.github/workflows/eslint-code-scanning.yml
index 81a261de..a7b0be94 100644
--- a/.github/workflows/eslint-code-scanning.yml
+++ b/.github/workflows/eslint-code-scanning.yml
@@ -37,7 +37,7 @@ jobs:
       - name: Set up Node.js
         uses: actions/setup-node@v6
         with:
-          node-version: 24.x
+          node-version: 26.x
 
       - name: Install ESLint
         run: |
diff --git a/.github/workflows/eslint.yml b/.github/workflows/eslint.yml
index 16fd64bb..cb3a1222 100644
--- a/.github/workflows/eslint.yml
+++ b/.github/workflows/eslint.yml
@@ -36,7 +36,7 @@ jobs:
     strategy:
       matrix:
         os: ["ubuntu-24.04", "macos-14", "windows-2022"]
-        node-version: [18.x, 20.x, 22.x]
+        node-version: [22.x, 24.x, 26.x]
         # See supported Node.js release schedule
         # at https://nodejs.org/en/about/releases/
     permissions:
@@ -52,8 +52,7 @@ jobs:
       - name: Set up Node.js
         uses: actions/setup-node@v6
         with:
-          node-version: 24.x
-
+          node-version: ${{ matrix.node-version }}
       - name: Install ESLint
         run: |
           npm install
diff --git a/.github/workflows/make-coverage-html.yml b/.github/workflows/make-coverage-html.yml
index 7ea86c32..c19d8eff 100644
--- a/.github/workflows/make-coverage-html.yml
+++ b/.github/workflows/make-coverage-html.yml
@@ -26,7 +26,7 @@ jobs:
       - name: Set up Node.js
         uses: actions/setup-node@v6
         with:
-          node-version: 24.x
+          node-version: 26.x
 
       - name: Tool test
         run: |
diff --git a/.github/workflows/markdown-lint.yml b/.github/workflows/markdown-lint.yml
index a80dc93a..9290043c 100644
--- a/.github/workflows/markdown-lint.yml
+++ b/.github/workflows/markdown-lint.yml
@@ -19,7 +19,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [22.x]
+        node-version: [26.x]
         # See supported Node.js release schedule
         # at https://nodejs.org/en/about/releases/
 
diff --git a/.github/workflows/node-coverage.js.yml b/.github/workflows/node-coverage.js.yml
index e32b2537..b3269b21 100644
--- a/.github/workflows/node-coverage.js.yml
+++ b/.github/workflows/node-coverage.js.yml
@@ -22,7 +22,7 @@ jobs:
       - name: Set up Node.js
         uses: actions/setup-node@v6
         with:
-          node-version: 24.x
+          node-version: 26.x
 
       - name: Tool test
         run: |
diff --git a/Dockerfile b/Dockerfile
index a91b5422..50020668 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-ARG BASE_IMAGE=node:24.16.0-alpine3.23
+ARG BASE_IMAGE=node:26.3.0-alpine3.23
 
 ###############################################################################
 FROM ${BASE_IMAGE} AS base