GHSA-9c5c-5j4h-8q2c is a medium-severity (CVSS 5.3) CWE-284 vulnerability in ssddanbrown/bookstack. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-9c5c-5j4h-8q2c is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
BookStack is vulnerable to Improper Access Control.
Real-World Exposure
ssddanbrown/bookstackReal-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
BookStack prior to version 21.11.3 is vulnerable to Improper Access Control. A logged-in user with no privileges OR guest user (if public access enabled) can access the /search/users/select AJAX endpoint meant for admins to manage audit logs, to dump all usernames existing in the Bookstack database. This can also be used to harvest email belonging to a user because BookStack also uses the code where(email, like, % . $search . %) to search for users based on email.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | ssddanbrown/bookstack | all versions | 21.11.3 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ssddanbrown/bookstack. 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 ssddanbrown/bookstack to 21.11.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9c5c-5j4h-8q2c 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-9c5c-5j4h-8q2c 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-9c5c-5j4h-8q2c. 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-9c5c-5j4h-8q2c in your dependencies?
O3 detects GHSA-9c5c-5j4h-8q2c across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.