diff --git a/system/Helpers/security_helper.php b/system/Helpers/security_helper.php
index d42ac0dda777..d73fd6219b12 100644
--- a/system/Helpers/security_helper.php
+++ b/system/Helpers/security_helper.php
@@ -15,11 +15,69 @@
 
 if (! function_exists('sanitize_filename')) {
     /**
-     * Sanitize a filename to use in a URI.
+     * Sanitize Filename
+     *
+     * Tries to sanitize filenames in order to prevent directory traversal attempts
+     * and other security threats, which is particularly useful for files that
+     * were supplied via user input.
+     *
+     * If it is acceptable for the user input to include relative paths,
+     * e.g. file/in/some/approved/folder.txt, you can set the second optional
+     * parameter, $relativePath to TRUE.
+     *
+     * @param string $filename     Input file name
+     * @param bool   $relativePath Whether to preserve paths
      */
-    function sanitize_filename(string $filename): string
+    function sanitize_filename(string $filename, bool $relativePath = false): string
     {
-        return service('security')->sanitizeFilename($filename);
+        // List of sanitized filename strings
+        $bad = [
+            '../',
+            '<!--',
+            '-->',
+            '<',
+            '>',
+            "'",
+            '"',
+            '&',
+            '$',
+            '#',
+            '{',
+            '}',
+            '[',
+            ']',
+            '=',
+            ';',
+            '?',
+            '%20',
+            '%22',
+            '%3c',
+            '%253c',
+            '%3e',
+            '%0e',
+            '%28',
+            '%29',
+            '%2528',
+            '%26',
+            '%24',
+            '%3f',
+            '%3b',
+            '%3d',
+        ];
+
+        if (! $relativePath) {
+            $bad[] = './';
+            $bad[] = '/';
+        }
+
+        $filename = remove_invisible_characters($filename, false);
+
+        do {
+            $old      = $filename;
+            $filename = str_replace($bad, '', $filename);
+        } while ($old !== $filename);
+
+        return stripslashes($filename);
     }
 }
 
diff --git a/system/Security/Security.php b/system/Security/Security.php
index 9e87a2177cda..aa744d9ed343 100644
--- a/system/Security/Security.php
+++ b/system/Security/Security.php
@@ -427,59 +427,16 @@ public function shouldRedirect(): bool
      * e.g. file/in/some/approved/folder.txt, you can set the second optional
      * parameter, $relativePath to TRUE.
      *
+     * @deprecated 4.6.2 Use `sanitize_filename()` instead
+     *
      * @param string $str          Input file name
      * @param bool   $relativePath Whether to preserve paths
      */
     public function sanitizeFilename(string $str, bool $relativePath = false): string
     {
-        // List of sanitize filename strings
-        $bad = [
-            '../',
-            '<!--',
-            '-->',
-            '<',
-            '>',
-            "'",
-            '"',
-            '&',
-            '$',
-            '#',
-            '{',
-            '}',
-            '[',
-            ']',
-            '=',
-            ';',
-            '?',
-            '%20',
-            '%22',
-            '%3c',
-            '%253c',
-            '%3e',
-            '%0e',
-            '%28',
-            '%29',
-            '%2528',
-            '%26',
-            '%24',
-            '%3f',
-            '%3b',
-            '%3d',
-        ];
-
-        if (! $relativePath) {
-            $bad[] = './';
-            $bad[] = '/';
-        }
-
-        $str = remove_invisible_characters($str, false);
-
-        do {
-            $old = $str;
-            $str = str_replace($bad, '', $str);
-        } while ($old !== $str);
+        helper('security');
 
-        return stripslashes($str);
+        return sanitize_filename($str, $relativePath);
     }
 
     /**
diff --git a/system/Security/SecurityInterface.php b/system/Security/SecurityInterface.php
index 03a5ba2321d0..ebd8919cd109 100644
--- a/system/Security/SecurityInterface.php
+++ b/system/Security/SecurityInterface.php
@@ -66,6 +66,8 @@ public function shouldRedirect(): bool;
      * e.g. file/in/some/approved/folder.txt, you can set the second optional
      * parameter, $relativePath to TRUE.
      *
+     * @deprecated 4.6.2 Use `sanitize_filename()` instead
+     *
      * @param string $str          Input file name
      * @param bool   $relativePath Whether to preserve paths
      */
diff --git a/user_guide_src/source/changelogs/v4.6.2.rst b/user_guide_src/source/changelogs/v4.6.2.rst
index dd988c4778b5..089fb01e1514 100644
--- a/user_guide_src/source/changelogs/v4.6.2.rst
+++ b/user_guide_src/source/changelogs/v4.6.2.rst
@@ -22,14 +22,21 @@ Message Changes
 Changes
 *******
 
+- **Security:** The ``sanitize_filename()`` function from the Security helper now supports a second parameter to control whether relative paths are allowed.
+
 ************
 Deprecations
 ************
 
+- **Security:** The ``Security::sanitizeFilename()`` method is deprecated. Use ``sanitize_filename()`` instead.
+- **Security:** The ``SecurityInterface::sanitizeFilename()`` method is deprecated.
+
 **********
 Bugs Fixed
 **********
 
+- **Security:** Fixed a bug where the ``sanitize_filename()`` function from the Security helper would throw an error when used in CLI requests.
+
 See the repo's
 `CHANGELOG.md <https://github.com/codeigniter4/CodeIgniter4/blob/develop/CHANGELOG.md>`_
 for a complete list of bugs fixed.
diff --git a/user_guide_src/source/helpers/security_helper.rst b/user_guide_src/source/helpers/security_helper.rst
index 500b7fd85b11..405a6e489051 100644
--- a/user_guide_src/source/helpers/security_helper.rst
+++ b/user_guide_src/source/helpers/security_helper.rst
@@ -20,15 +20,15 @@ Available Functions
 
 The following functions are available:
 
-.. php:function:: sanitize_filename($filename)
+.. php:function:: sanitize_filename($filename[, $relativePath = false])
 
     :param    string    $filename: Filename
+    :param    bool      $relativePath: Whether the relative path is acceptable (available since v4.6.2)
     :returns:    Sanitized file name
     :rtype:    string
 
     Provides protection against directory traversal.
 
-    This function is an alias for ``\CodeIgniter\Security::sanitizeFilename()``.
     For more info, please see the :doc:`Security Library <../libraries/security>`
     documentation.
 
diff --git a/user_guide_src/source/libraries/security.rst b/user_guide_src/source/libraries/security.rst
index 07e2e8756d18..8fc49d646b1a 100644
--- a/user_guide_src/source/libraries/security.rst
+++ b/user_guide_src/source/libraries/security.rst
@@ -241,3 +241,5 @@ If it is acceptable for the user input to include relative paths, e.g., **file/i
 the second optional parameter, ``$relativePath`` to ``true``.
 
 .. literalinclude:: security/010.php
+
+This method is an alias for the ``sanitize_filename()`` function from the Security helper.