diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index a0e2bd033aa..9e8e898b3d7 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -65,8 +65,13 @@ jobs:
         uses: niden/actions-memcached@v7
 
       - name: Install dependencies.
+        if: matrix.php != '8.4'
         run: composer update $DEFAULT_COMPOSER_FLAGS
 
+      - name: Install dependencies with PHP 8.4.
+        if: matrix.php == '8.4'
+        run: composer update $DEFAULT_COMPOSER_FLAGS --ignore-platform-reqs
+
       - name: Run tests with PHPUnit and generate coverage.
         if: matrix.php == '7.4'
         run: vendor/bin/phpunit --verbose --exclude-group $PHPUNIT_EXCLUDE_GROUP --coverage-clover=coverage.xml --colors=always
diff --git a/.github/workflows/ci-mssql.yml b/.github/workflows/ci-mssql.yml
index 698cf613040..5ed0abcb763 100644
--- a/.github/workflows/ci-mssql.yml
+++ b/.github/workflows/ci-mssql.yml
@@ -66,8 +66,13 @@ jobs:
         run: composer self-update
 
       - name: Install dependencies with composer
+        if: matrix.php != '8.4'
         run: composer update --prefer-dist --no-interaction --no-progress --optimize-autoloader --ansi
 
+      - name: Install dependencies with PHP 8.4.
+        if: matrix.php == '8.4'
+        run: composer update --prefer-dist --no-interaction --no-progress --optimize-autoloader --ignore-platform-reqs --ansi
+
       - name: Run MSSQL tests with PHPUnit and generate coverage.
         run: vendor/bin/phpunit --group mssql --coverage-clover=coverage.xml --colors=always
 
diff --git a/.github/workflows/ci-mysql.yml b/.github/workflows/ci-mysql.yml
index 7bec2352248..5753d916958 100644
--- a/.github/workflows/ci-mysql.yml
+++ b/.github/workflows/ci-mysql.yml
@@ -47,9 +47,14 @@ jobs:
           php-version: ${{ matrix.php }}
           tools: composer:v2, pecl
 
-      - name: Install dependencies with composer.
+      - name: Install dependencies with composer
+        if: matrix.php != '8.4'
         run: composer update --prefer-dist --no-interaction --no-progress --optimize-autoloader --ansi
 
+      - name: Install dependencies with PHP 8.4.
+        if: matrix.php == '8.4'
+        run: composer update --prefer-dist --no-interaction --no-progress --optimize-autoloader --ignore-platform-reqs --ansi
+
       - name: Run MySQL tests with PHPUnit and generate coverage.
         run: vendor/bin/phpunit --group mysql --coverage-clover=coverage.xml --colors=always
 
diff --git a/.github/workflows/ci-pgsql.yml b/.github/workflows/ci-pgsql.yml
index 8dd8b3d6da5..4b926645b82 100644
--- a/.github/workflows/ci-pgsql.yml
+++ b/.github/workflows/ci-pgsql.yml
@@ -51,9 +51,14 @@ jobs:
       - name: Update composer.
         run: composer self-update
 
-      - name: Install dependencies with composer.
+      - name: Install dependencies with composer
+        if: matrix.php != '8.4'
         run: composer update --prefer-dist --no-interaction --no-progress --optimize-autoloader --ansi
 
+      - name: Install dependencies with PHP 8.4.
+        if: matrix.php == '8.4'
+        run: composer update --prefer-dist --no-interaction --no-progress --optimize-autoloader --ignore-platform-reqs --ansi
+
       - name: Run Pgsql tests with PHPUnit and generate coverage.
         run: vendor/bin/phpunit --group pgsql --coverage-clover=coverage.xml --colors=always
 
diff --git a/.github/workflows/ci-sqlite.yml b/.github/workflows/ci-sqlite.yml
index bf53dc35975..fe7405ea4e2 100644
--- a/.github/workflows/ci-sqlite.yml
+++ b/.github/workflows/ci-sqlite.yml
@@ -40,9 +40,14 @@ jobs:
       - name: Update composer.
         run: composer self-update
 
-      - name: Install dependencies with composer.
+      - name: Install dependencies with composer
+        if: matrix.php != '8.4'
         run: composer update --prefer-dist --no-interaction --no-progress --optimize-autoloader --ansi
 
+      - name: Install dependencies with PHP 8.4.
+        if: matrix.php == '8.4'
+        run: composer update --prefer-dist --no-interaction --no-progress --optimize-autoloader --ignore-platform-reqs --ansi
+
       - name: Run SQLite tests with PHPUnit and generate coverage.
         run: vendor/bin/phpunit --group sqlite --coverage-clover=coverage.xml --colors=always
 
diff --git a/composer.json b/composer.json
index 90dc2720717..af172dbb762 100644
--- a/composer.json
+++ b/composer.json
@@ -73,7 +73,7 @@
         "ext-ctype": "*",
         "lib-pcre": "*",
         "yiisoft/yii2-composer": "~2.0.4",
-        "ezyang/htmlpurifier": "^4.6",
+        "ezyang/htmlpurifier": "^4.17",
         "cebe/markdown": "~1.0.0 | ~1.1.0 | ~1.2.0",
         "bower-asset/jquery": "3.7.*@stable | 3.6.*@stable | 3.5.*@stable | 3.4.*@stable | 3.3.*@stable | 3.2.*@stable | 3.1.*@stable | 2.2.*@stable | 2.1.*@stable | 1.11.*@stable | 1.12.*@stable",
         "bower-asset/inputmask": "^5.0.8 ",
diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index 57567d20712..84c56493049 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -22,7 +22,7 @@ Yii Framework 2 Change Log
 - Enh #20034: Added `yii\helpers\BaseStringHelper::findBetween()` to retrieve a substring that lies between two strings (salehhashemi1992)
 - Enh #20121: Added `yiisoft/yii2-coding-standards` to composer `require-dev` and lint code to comply with PSR12 (razvanphp)
 - Enh #20134: Raise minimum `PHP` version to `7.3` (@terabytesoftw)
-
+- Bug #20141: Update `ezyang/htmlpurifier` dependency to version `4.17` (@terabytesoftw)
 
 2.0.49.2 October 12, 2023
 -------------------------
diff --git a/framework/composer.json b/framework/composer.json
index 37c438afb17..d24703fb442 100644
--- a/framework/composer.json
+++ b/framework/composer.json
@@ -68,7 +68,7 @@
         "ext-ctype": "*",
         "lib-pcre": "*",
         "yiisoft/yii2-composer": "~2.0.4",
-        "ezyang/htmlpurifier": "^4.6",
+        "ezyang/htmlpurifier": "^4.17",
         "cebe/markdown": "~1.0.0 | ~1.1.0 | ~1.2.0",
         "bower-asset/jquery": "3.7.*@stable | 3.6.*@stable | 3.5.*@stable | 3.4.*@stable | 3.3.*@stable | 3.2.*@stable | 3.1.*@stable | 2.2.*@stable | 2.1.*@stable | 1.11.*@stable | 1.12.*@stable",
         "bower-asset/inputmask": "^5.0.8 ",