system/src/Grav/Framework/Cache/Adapter/FileCache.phpunserialize($value, ['allowed_classes' => true])>= 1.7.44 and <= 1.7.49.5 (verified in current codebase and changelog-covered releases).1.7.x releases may also be affected, but were not fully back-traced in this review.allowed_classes => true allows object instantiation and does not constrain classes.
php -r '
class CacheWakeup { public function __wakeup(){ file_put_contents("/tmp/grav_filecache_poc.txt", "wakeup"); } }
$payload = serialize(new CacheWakeup());
unserialize($payload, ["allowed_classes" => true]);
echo file_exists("/tmp/grav_filecache_poc.txt") ? "FILECACHE_UNSERIALIZE_TRIGGERED\n" : "FILECACHE_UNSERIALIZE_NOT_TRIGGERED\n";
'
FILECACHE_UNSERIALIZE_TRIGGERED.This reproduces the same unsafe primitive used by FileCache::doGet():
unserialize($value, ['allowed_classes' => true]).
If cache files are attacker-tampered, object magic methods may execute.
Fixed in Grav core on the 2.0 branch: commit c66dfeb5f — will ship in 2.0.0-beta.2.
What changed: Framework\Cache\Adapter\FileCache now HMAC-signs every cache payload with Security::getNonceKey() on write, and verifies the HMAC on read. Tampered, forged, or pre-upgrade files are treated as cache misses and unlinked instead of being unserialized. The on-disk format is now versioned:
v2
<expires>
<key>
<hmac-hex>
<serialized>
Existing caches rebuild transparently on first read. Note that Framework\Cache\Adapter\FileCache isn't wired into Grav's main cache path — Symfony's FilesystemAdapter is — but the class is reachable by plugin and downstream consumers, so the hardening applies defensively.
Files:
system/src/Grav/Framework/Cache/Adapter/FileCache.php.tests/unit/Grav/Common/Security/FileCacheSecurityTest.php — round-trip, tampered-payload rejection, wrong-key forgery rejection, pre-v2 file rebuild, key-field mismatch.{
"cwe_ids": [
"CWE-20",
"CWE-502"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-05T21:29:29Z",
"nvd_published_at": null,
"severity": "LOW"
}