GHSA-gwfr-jfjf-92vv is a medium-severity (CVSS 5) Improper Input Validation vulnerability in getgrav/grav. A fix is available for getgrav/grav — see the affected versions and patch details below.
Grav has Insecure Deserialization in File Cache
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-gwfr-jfjf-92vv.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-gwfr-jfjf-92vv plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
getgrav/gravReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Insecure Deserialization in File Cache
- Severity: High
- CWE: CWE-502
- Location:
system/src/Grav/Framework/Cache/Adapter/FileCache.php - Sink:
unserialize($value, ['allowed_classes' => true])
Affected version(s)
- Affected:
>= 1.7.44and<= 1.7.49.5(verified in current codebase and changelog-covered releases). - Fixed: No upstream fix identified in the reviewed branch at the time of analysis.
- Notes: Earlier
1.7.xreleases may also be affected, but were not fully back-traced in this review.
Notes
allowed_classes => true allows object instantiation and does not constrain classes.
PoC (Primitive Demonstration)
Preconditions
- Local PHP runtime.
- Goal is to validate the deserialization primitive used in cache retrieval.
Steps
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";
'
Expected Result
- Output contains:
FILECACHE_UNSERIALIZE_TRIGGERED.
Interpretation
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.
Exploit Preconditions
- Cache file poisoning/tampering capability.
Recommendation
- Avoid object deserialization in cache payloads.
- Use non-object formats and integrity protection for cache files.
Maintainer note — fix applied (2026-04-24)
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | getgrav/grav | all versions | 2.0.0-beta.2composer require getgrav/grav:^2.0.0-beta.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for getgrav/grav, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update getgrav/grav to 2.0.0-beta.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-gwfr-jfjf-92vv is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-gwfr-jfjf-92vv can be triaged on real exposure rather than presence alone.
Tailored to GHSA-gwfr-jfjf-92vv. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-gwfr-jfjf-92vv in your dependencies?
O3 Security finds GHSA-gwfr-jfjf-92vv across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.