diff --git a/.gitignore b/.gitignore
index b0c31dd..24de360 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@
 composer.lock
 package-lock.json
 /lib/
+tests/.phpunit.result.cache
\ No newline at end of file
diff --git a/Modules/Sfw.php b/Modules/Sfw.php
index d5da741..1205141 100644
--- a/Modules/Sfw.php
+++ b/Modules/Sfw.php
@@ -286,6 +286,8 @@ public function diePage($result)
                 $request_uri = preg_replace('%sfw_test_ip=\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}&?%', '', $request_uri);
             }
 
+            $request_uri = htmlspecialchars($request_uri, ENT_QUOTES | ENT_HTML5, 'UTF-8');
+
             // @ToDo not implemented yet
             // Custom Logo
             //$custom_logo_img = '';
diff --git a/composer.json b/composer.json
index 0aa27ca..d8b6669 100644
--- a/composer.json
+++ b/composer.json
@@ -24,7 +24,7 @@
   },
   "require-dev": {
     "vimeo/psalm": "^4.8",
-    "phpunit/phpunit": "^7.5",
+    "phpunit/phpunit": "^8.5.52",
     "squizlabs/php_codesniffer": "3.*",
     "phpcompatibility/php-compatibility": "^9.3"
   },
@@ -41,5 +41,10 @@
     "psr-4": {
       "Cleantalk\\Common\\Firewall\\": "/"
     }
+  },
+  "config": {
+    "allow-plugins": {
+      "cleantalk/apbct-installer": true
+    }
   }
 }
diff --git a/tests/Modules/SFW/SfwXssProtectionTest.php b/tests/Modules/SFW/SfwXssProtectionTest.php
new file mode 100644
index 0000000..4393891
--- /dev/null
+++ b/tests/Modules/SFW/SfwXssProtectionTest.php
@@ -0,0 +1,174 @@
+<?php
+
+namespace Cleantalk\Common\Firewall\Tests;
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Tests for XSS protection in Sfw::diePage() method, specifically focusing on sanitization of REQUEST_URI to prevent XSS attacks.
+ */
+class SfwXssProtectionTest extends TestCase
+{
+    /**
+     * Checks that malicious input in REQUEST_URI is properly sanitized to prevent XSS attacks
+     *
+     * @dataProvider xssPayloadProvider
+     */
+    public function testRequestUriXssSanitization($maliciousInput, $expectedOutput)
+    {
+        // Emulate the sanitization logic from Sfw::diePage()
+        $sanitized = htmlspecialchars($maliciousInput, ENT_QUOTES | ENT_HTML5, 'UTF-8');
+        
+        $this->assertSame($expectedOutput, $sanitized);
+        
+        // Additional check: the result should not contain unescaped tags
+        $this->assertStringNotContainsString('<script', $sanitized);
+    }
+
+    /**
+     * Checks that safe URLs remain functional after sanitization
+     *
+     * @dataProvider safeUrlProvider
+     */
+    public function testSafeUrlsRemainFunctional($safeUrl)
+    {
+        $sanitized = htmlspecialchars($safeUrl, ENT_QUOTES | ENT_HTML5, 'UTF-8');
+        
+        // URL should retain its structure (path and query string)
+        $this->assertStringContainsString('/', $sanitized);
+    }
+
+    /**
+     * Data provider with various XSS payloads
+     */
+    public static function xssPayloadProvider(): array
+    {
+        return [
+            'basic script tag' => [
+                '/<script>alert("XSS")</script>',
+                '/&lt;script&gt;alert(&quot;XSS&quot;)&lt;/script&gt;'
+            ],
+            'script with single quotes' => [
+                "/<script>alert('XSS')</script>",
+                '/&lt;script&gt;alert(&apos;XSS&apos;)&lt;/script&gt;'
+            ],
+            'img onerror' => [
+                '/<img src=x onerror=alert(1)>',
+                '/&lt;img src=x onerror=alert(1)&gt;'
+            ],
+            'svg onload' => [
+                '/<svg onload=alert(1)>',
+                '/&lt;svg onload=alert(1)&gt;'
+            ],
+            'javascript protocol' => [
+                '/page?url=javascript:alert(1)',
+                '/page?url=javascript:alert(1)'
+            ],
+            'encoded angle brackets' => [
+                '/page?q=%3Cscript%3Ealert(1)%3C/script%3E',
+                '/page?q=%3Cscript%3Ealert(1)%3C/script%3E'
+            ],
+            'double quotes in attribute' => [
+                '/page?name="><script>alert(1)</script>',
+                '/page?name=&quot;&gt;&lt;script&gt;alert(1)&lt;/script&gt;'
+            ],
+            'single quotes in attribute' => [
+                "/page?name='><script>alert(1)</script>",
+                '/page?name=&apos;&gt;&lt;script&gt;alert(1)&lt;/script&gt;'
+            ],
+            'event handler injection' => [
+                '/page" onmouseover="alert(1)',
+                '/page&quot; onmouseover=&quot;alert(1)'
+            ],
+            'mixed quotes' => [
+                '/page?a="test\'value"',
+                '/page?a=&quot;test&apos;value&quot;'
+            ],
+            'html entities' => [
+                '/page?q=<b>bold</b>&amp;test',
+                '/page?q=&lt;b&gt;bold&lt;/b&gt;&amp;amp;test'
+            ],
+        ];
+    }
+
+    /**
+     * Data provider with safe URLs
+     */
+    public static function safeUrlProvider(): array
+    {
+        return [
+            'simple path' => ['/page'],
+            'path with query' => ['/page?id=123'],
+            'path with multiple params' => ['/page?id=123&name=test'],
+            'nested path' => ['/admin/users/edit'],
+            'path with numbers' => ['/article/2024/01/15'],
+            'path with hyphens' => ['/my-page-url'],
+            'path with underscores' => ['/my_page_url'],
+            'root path' => ['/'],
+            'path with hash fragment' => ['/page#section'],
+            'complex query string' => ['/search?q=test+query&page=1&sort=asc'],
+        ];
+    }
+
+    /**
+     * Checks that an empty string is handled correctly
+     */
+    public function testEmptyRequestUri()
+    {
+        $sanitized = htmlspecialchars('', ENT_QUOTES | ENT_HTML5, 'UTF-8');
+        $this->assertSame('', $sanitized);
+    }
+
+    /**
+     * Checks that null is converted to an empty string
+     */
+    public function testNullRequestUri()
+    {
+        $sanitized = htmlspecialchars((string)null, ENT_QUOTES | ENT_HTML5, 'UTF-8');
+        $this->assertSame('', $sanitized);
+    }
+
+    /**
+     * Checks that UTF-8 characters are preserved
+     */
+    public function testUtf8Characters()
+    {
+        $input = '/page?query=test';
+        $sanitized = htmlspecialchars($input, ENT_QUOTES | ENT_HTML5, 'UTF-8');
+        
+        // UTF-8 characters should remain unchanged
+        $this->assertSame($input, $sanitized);
+    }
+
+    /**
+     * Checks that the sfw_test_ip parameter is correctly removed before sanitization
+     */
+    public function testSfwTestIpRemoval()
+    {
+        $input = '/page?sfw_test_ip=192.168.1.1&other=value';
+        
+        // Emulate the logic from Sfw::diePage()
+        $request_uri = preg_replace('%sfw_test_ip=\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}&?%', '', $input);
+        $sanitized = htmlspecialchars($request_uri, ENT_QUOTES | ENT_HTML5, 'UTF-8');
+        
+        $this->assertStringNotContainsString('sfw_test_ip', $sanitized);
+        $this->assertStringContainsString('other=value', $sanitized);
+    }
+
+    /**
+     * Checks that XSS in sfw_test_ip does not pass even if the parameter is not completely removed
+     */
+    public function testSfwTestIpWithXssPayload()
+    {
+        // Attempted injection through an invalid IP
+        $input = '/page?sfw_test_ip=<script>alert(1)</script>&other=value';
+        
+        // Regex won't match (invalid IP), so the parameter remains
+        $request_uri = preg_replace('%sfw_test_ip=\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}&?%', '', $input);
+        $sanitized = htmlspecialchars($request_uri, ENT_QUOTES | ENT_HTML5, 'UTF-8');
+        
+        // XSS should still be escaped
+        $this->assertStringNotContainsString('<script>', $sanitized);
+        $this->assertStringContainsString('&lt;script&gt;', $sanitized);
+    }
+}