GHSA-h377-287m-w2r9
MEDIUMGHSA-h377-287m-w2r9 is a medium-severity (CVSS 5.9) Improper Input Validation vulnerability in drupal/core. O3 Security confirms whether GHSA-h377-287m-w2r9 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Drupal file REST resource does not properly validate
Real-World Exposure
drupal/core🐘drupal/drupalReal-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
In Drupal 8 prior to 8.3.4; The file REST resource does not properly validate some fields when manipulating files. A site is only affected by this if the site has the RESTful Web Services (rest) module enabled, the file REST resource is enabled and allows PATCH requests, and an attacker can get or register a user account on the site with permissions to upload files and to modify the file resource.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | drupal/core | ≥ 8.0&&< 8.3.4 | 8.3.4 |
| 🐘Packagist | drupal/drupal | ≥ 8.0&&< 8.3.4 | 8.3.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for drupal/core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update drupal/core to 8.3.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h377-287m-w2r9 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 pinpoints whether GHSA-h377-287m-w2r9 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-h377-287m-w2r9. 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-h377-287m-w2r9 in your dependencies?
O3 detects GHSA-h377-287m-w2r9 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.