diff --git a/cms/db/task.py b/cms/db/task.py
index 388a4a56d4..c753efdce1 100644
--- a/cms/db/task.py
+++ b/cms/db/task.py
@@ -6,6 +6,7 @@
 # Copyright © 2010-2012 Matteo Boscariol <boscarim@hotmail.com>
 # Copyright © 2012-2018 Luca Wehrstedt <luca.wehrstedt@gmail.com>
 # Copyright © 2013 Bernard Blackham <bernard@largestprime.net>
+# Copyright © 2025 Pasit Sangprachathanarak <ouipingpasit@gmail.com>
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as
@@ -116,6 +117,12 @@ class Task(Base):
         nullable=False,
         default=[])
 
+    # The list of names of programming languages allowed for this task.
+    # If null, all contest languages are allowed.
+    allowed_languages: list[str] | None = Column(
+        ARRAY(String), nullable=True, default=None
+    )
+
     # The parameters that control task-tokens follow. Note that their
     # effect during the contest depends on the interaction with the
     # parameters that control contest-tokens, defined on the Contest.
@@ -272,6 +279,21 @@ class Task(Base):
         passive_deletes=True,
         back_populates="task")
 
+    def get_allowed_languages(self) -> list[str] | None:
+        """Get the list of allowed languages for this task.
+
+        If the task has specific allowed languages configured, return those.
+        Otherwise, return the contest's allowed languages.
+
+        return: list of allowed language names, or None if no contest is set
+        """
+        # If task has specific language restrictions, use those
+        if self.allowed_languages is not None:
+            return self.allowed_languages
+
+        # Otherwise, use contest language restrictions
+        return self.contest.languages if self.contest else None
+
 
 class Statement(Base):
     """Class to store a translation of the task statement.
diff --git a/cms/server/admin/handlers/task.py b/cms/server/admin/handlers/task.py
index 5f44017a1b..77aed67613 100644
--- a/cms/server/admin/handlers/task.py
+++ b/cms/server/admin/handlers/task.py
@@ -8,6 +8,7 @@
 # Copyright © 2014 Artem Iglikov <artem.iglikov@gmail.com>
 # Copyright © 2014 Fabian Gundlach <320pointsguy@gmail.com>
 # Copyright © 2016 Myungwoo Chun <mc.tamaki@gmail.com>
+# Copyright © 2025 Pasit Sangprachathanarak <ouipingpasit@gmail.com>
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as
@@ -147,6 +148,14 @@ def post(self, task_id):
             self.get_submission_format(attrs)
             self.get_string(attrs, "feedback_level")
 
+            # Process allowed languages
+            selected_languages = self.get_arguments("allowed_languages")
+            if not selected_languages:
+                # No languages selected means allow all contest languages (NULL)
+                attrs["allowed_languages"] = None
+            else:
+                attrs["allowed_languages"] = selected_languages
+
             self.get_string(attrs, "token_mode")
             self.get_int(attrs, "token_max_number")
             self.get_timedelta_sec(attrs, "token_min_interval")
diff --git a/cms/server/admin/static/aws_style.css b/cms/server/admin/static/aws_style.css
index 1dce90fcb3..cd442a3514 100644
--- a/cms/server/admin/static/aws_style.css
+++ b/cms/server/admin/static/aws_style.css
@@ -382,6 +382,15 @@ table td.wrapping-options label {
     margin-right: 15px;
 }
 
+.language-item label {
+    display: block;
+    white-space: nowrap;
+    cursor: pointer;
+}
+
+.language-item input[type="checkbox"] {
+    margin-right: 6px;
+}
 table td.partial::after {
     content: "*";
 }
diff --git a/cms/server/admin/templates/task.html b/cms/server/admin/templates/task.html
index 00c6759cb7..0623a69849 100644
--- a/cms/server/admin/templates/task.html
+++ b/cms/server/admin/templates/task.html
@@ -130,6 +130,19 @@ <h2 id="title_task_configuration" class="toggling_on">Task configuration</h2>
           <input type="text" name="submission_format" value="{{ task.submission_format|join(", ") }}"/>
         </td>
       </tr>
+      <tr>
+        <td>
+          <span class="info" title="Programming languages that contestants can use to solve this task.
+                                    If none are selected, all contest languages are allowed.
+                                    Otherwise, only the selected languages (which must be a subset of contest languages) are allowed."></span>
+          Allowed programming languages
+        </td>
+        <td class="wrapping-options">
+          {% for lang in LANGUAGES %}
+            <label><input type="checkbox" name="allowed_languages" value="{{ lang.name }}" {{ "checked" if task.allowed_languages is none or lang.name in (task.allowed_languages or []) else "" }}>{{ lang.name }}</label>
+          {% endfor %}
+        </td>
+      </tr>
       <tr>
         <td>
           <span class="info" title="With 'restricted' contestants only see limited technical information about each testcase; with 'full' they see more details, but malicious contestants might use this data to get some information about the test data."></span>
diff --git a/cms/server/contest/static/cws_utils.js b/cms/server/contest/static/cws_utils.js
index 23ab394f9c..aa86dc7161 100644
--- a/cms/server/contest/static/cws_utils.js
+++ b/cms/server/contest/static/cws_utils.js
@@ -338,7 +338,9 @@ CMS.CWSUtils.prototype.switch_lang = function() {
     location.reload();
 };
 
-CMS.CWSUtils.filter_languages = function(options, inputs) {
+CMS.CWSUtils.filter_languages = function (options, inputs, languages) {
+    languages = languages || LANGUAGES;
+
     var exts = [];
     for (var i = 0; i < inputs.length; i++) {
         exts.push('.' + inputs[i].value.match(/[^.]*$/)[0]);
@@ -346,9 +348,9 @@ CMS.CWSUtils.filter_languages = function(options, inputs) {
     // Find all languages that should be enabled.
     var enabled = {};
     var anyEnabled = false;
-    for (var lang in LANGUAGES) {
+    for (var lang in languages) {
         for (i = 0; i < exts.length; i++) {
-            if (LANGUAGES[lang][exts[i]]) {
+            if (languages[lang][exts[i]]) {
                 enabled[lang] = true;
                 anyEnabled = true;
                 break;
diff --git a/cms/server/contest/submission/workflow.py b/cms/server/contest/submission/workflow.py
index 9210fbd80f..a421427eb8 100644
--- a/cms/server/contest/submission/workflow.py
+++ b/cms/server/contest/submission/workflow.py
@@ -11,6 +11,7 @@
 # Copyright © 2015-2016 William Di Luigi <williamdiluigi@gmail.com>
 # Copyright © 2016 Myungwoo Chun <mc.tamaki@gmail.com>
 # Copyright © 2016 Amir Keivan Mohtashami <akmohtashami97@gmail.com>
+# Copyright © 2025 Pasit Sangprachathanarak <ouipingpasit@gmail.com>
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as
@@ -195,8 +196,11 @@ def accept_submission(
 
     try:
         files, language = match_files_and_language(
-            received_files, language_name, required_codenames,
-            contest.languages)
+            received_files,
+            language_name,
+            required_codenames,
+            task.get_allowed_languages(),
+        )
     except InvalidFilesOrLanguage as err:
         logger.info(f'Submission rejected: {err}')
         raise UnacceptableSubmission(
@@ -398,8 +402,11 @@ def accept_user_test(
 
     try:
         files, language = match_files_and_language(
-            received_files, language_name, required_codenames,
-            contest.languages)
+            received_files,
+            language_name,
+            required_codenames,
+            task.get_allowed_languages(),
+        )
     except InvalidFilesOrLanguage as err:
         logger.info(f'Test rejected: {err}')
         raise UnacceptableUserTest(
diff --git a/cms/server/contest/templates/overview.html b/cms/server/contest/templates/overview.html
index 37fe202e3e..9d70120e13 100644
--- a/cms/server/contest/templates/overview.html
+++ b/cms/server/contest/templates/overview.html
@@ -205,8 +205,9 @@ <h2>{% trans %}Task overview{% endtrans %}</h2>
         </tr>
     </thead>
     <tbody>
-{% set extensions = "[%s]"|format(contest.languages|map("to_language")|map(attribute="source_extension")|unique|join("|")) %}
 {% for t_iter in contest.tasks %}
+        {% set task_allowed_languages = t_iter.get_allowed_languages() %}
+        {% set extensions = "[%s]"|format(task_allowed_languages|map("to_language")|map(attribute="source_extension")|unique|join("|")) %}
         <tr>
             <th>{{ t_iter.name }}</th>
             <td>{{ t_iter.title }}</td>
diff --git a/cms/server/contest/templates/task_description.html b/cms/server/contest/templates/task_description.html
index b560ab9bea..2948274a14 100644
--- a/cms/server/contest/templates/task_description.html
+++ b/cms/server/contest/templates/task_description.html
@@ -118,7 +118,8 @@ <h2>{% trans %}Some details{% endtrans %}</h2>
 {% endif %}
 {% set compilation_commands = task_type.get_compilation_commands(task.submission_format) %}
 {% if compilation_commands is not none %}
-{% set compilation_commands = compilation_commands|dictselect("in", contest.languages, by="key") %}
+{% set allowed_languages = task.get_allowed_languages() %}
+{% set compilation_commands = compilation_commands|dictselect("in", allowed_languages, by="key") %}
 <tr>
     <th rowspan="{{ compilation_commands|length }}">{% trans %}Compilation commands{% endtrans %}</th>
     {% for l, c in compilation_commands|dictsort(by="key") %}
diff --git a/cms/server/contest/templates/task_submissions.html b/cms/server/contest/templates/task_submissions.html
index 6105d17259..be1a439f56 100644
--- a/cms/server/contest/templates/task_submissions.html
+++ b/cms/server/contest/templates/task_submissions.html
@@ -6,6 +6,19 @@
 
 {% set score_type = get_score_type(dataset=task.active_dataset) %}
 
+{% block js_init %}
+// Define TASK_LANGUAGES for task-specific language filtering
+var TASK_LANGUAGES = {
+{% for lang in task.get_allowed_languages() or [] %}
+    '{{ lang }}': {
+{% for extension in (lang|to_language).source_extensions %}
+        '{{ extension }}': true,
+{% endfor %}
+    },
+{% endfor %}
+};
+{% endblock js_init %}
+
 {# Whether tokens are allowed on this contest. #}
 {% set can_use_tokens_in_contest =
        tokens_contest != TOKEN_MODE_DISABLED
@@ -254,7 +267,7 @@ <h2 style="margin-bottom: 10px">{% trans %}Submit a solution{% endtrans %}</h2>
                         <input type="file" class="input-xlarge"
                                id="input{{ loop.index0 }}" name="{{ filename }}"
                                onchange="CMS.CWSUtils.filter_languages($(this).parents('form').find('select[name=language] option'),
-                                                                       $(this).parents('form').find('input[type=file]'))"/>
+                                                                       $(this).parents('form').find('input[type=file]'), TASK_LANGUAGES)"/>
                     </div>
                 </div>
   {% endfor %}
@@ -262,7 +275,7 @@ <h2 style="margin-bottom: 10px">{% trans %}Submit a solution{% endtrans %}</h2>
                 <div class="control-group">
                     <div class="controls">
                         <select name="language">
-  {% for lang in contest.languages %}
+  {% for lang in task.get_allowed_languages() or [] %}
                             <option value="{{ lang }}">{{ lang }}</option>
   {% endfor %}
                         </select>
diff --git a/cms/server/contest/templates/test_interface.html b/cms/server/contest/templates/test_interface.html
index 33e2d178b2..49f49946f2 100644
--- a/cms/server/contest/templates/test_interface.html
+++ b/cms/server/contest/templates/test_interface.html
@@ -2,6 +2,19 @@
 
 {% set page = "test_interface" %}
 
+{% block js_init %}
+// Define TASK_LANGUAGES for task-specific language filtering
+var TASK_LANGUAGES = {
+{% for lang in task.get_allowed_languages() or [] %}
+    '{{ lang }}': {
+{% for extension in (lang|to_language).source_extensions %}
+        '{{ extension }}': true,
+{% endfor %}
+    },
+{% endfor %}
+};
+{% endblock js_init %}
+
 {% block additional_js %}
 $(document).on("click", ".user_test_list tbody tr td.status .details", function (event) {
     var $this = $(this);
@@ -105,7 +118,7 @@ <h2 style="margin-bottom: 10px">{% trans %}Submit a test{% endtrans %}</h2>
                         <input type="file" class="input-xlarge"
                                id="input{{ loop.index0 }}" name="{{ filename }}"
                                onchange="CMS.CWSUtils.filter_languages($(this).parents('form').find('select[name=language] option'),
-                                                                       $(this).parents('form').find('input[type=file]').not('#input_file'))"/>
+                                                                       $(this).parents('form').find('input[type=file]').not('#input_file'), TASK_LANGUAGES)"/>
                     </div>
                 </div>
 {% endfor %}
@@ -118,7 +131,7 @@ <h2 style="margin-bottom: 10px">{% trans %}Submit a test{% endtrans %}</h2>
                 <div class="control-group">
                     <div class="controls">
                         <select name="language">
-{% for lang in contest.languages %}
+{% for lang in task.get_allowed_languages() or [] %}
                             <option value="{{ lang }}">{{ lang }}</option>
 {% endfor %}
                         </select>
diff --git a/cmscontrib/updaters/update_from_1.5.sql b/cmscontrib/updaters/update_from_1.5.sql
index c22b736c6a..a1ff578498 100644
--- a/cmscontrib/updaters/update_from_1.5.sql
+++ b/cmscontrib/updaters/update_from_1.5.sql
@@ -42,4 +42,7 @@ ALTER TABLE user_test_results ADD COLUMN evaluation_sandbox_digests VARCHAR[];
 UPDATE user_test_results SET evaluation_sandbox_paths = string_to_array(evaluation_sandbox, ':');
 ALTER TABLE user_test_results DROP COLUMN evaluation_sandbox;
 
+-- https://github.com/cms-dev/cms/pull/1486
+ALTER TABLE public.tasks ADD COLUMN allowed_languages varchar[];
+
 COMMIT;