Drupal OAuth2 Server Missing Authorization vulnerabilityGHSA-4f8q-mwgc-3mwc
CRITICALGHSA-4f8q-mwgc-3mwc is a critical-severity (CVSS 9.8) CWE-862 vulnerability in drupal/oauth2_server. A fix is available for drupal/oauth2_server — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-4f8q-mwgc-3mwc.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
drupal/oauth2_serverReal-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
Missing Authorization vulnerability in Drupal OAuth2 Server allows Forceful Browsing. This issue affects OAuth2 Server: from 0.0.0 before 2.1.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | drupal/oauth2_server | all versions | 2.1.0composer require drupal/oauth2_server:^2.1.0 |
Affected Products
oauth2 serveroauth2_server_projectDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for drupal/oauth2_server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update drupal/oauth2_server to 2.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4f8q-mwgc-3mwc is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is GHSA-4f8q-mwgc-3mwc in your dependencies?
Find it across Packagist, including transitive dependencies.