GHSA-733r-8xcp-w9mr
MEDIUMFlarum's logout Route allows open redirects
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.
Blast Radius
flarum/core🐘flarum/frameworkReal-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
Impact
The Flarum /logout route includes a redirect parameter that allows any third party to redirect users from a (trusted) domain of the Flarum installation to redirect to any link. Sample: example.com/logout?return=https://google.com. For logged-in users, the logout must be confirmed. Guests are immediately redirected. This could be used by spammers to redirect to a web address using a trusted domain of a running Flarum installation.
Some ecosystem extensions modifying the logout route have already been affected. Sample: https://discuss.flarum.org/d/22229-premium-wordpress-integration/526
Patches
The vulnerability has been fixed and published as flarum/core v1.8.5. All communities running Flarum should upgrade as soon as possible to v1.8.5 using:
composer update --prefer-dist --no-dev -a -W
You can then confirm you run the latest version using:
composer show flarum/core
Workarounds
Some extensions modifying the logout route can remedy this issue if their implementation is safe. In any case we recommend updating to 1.8.5.
References
For any questions or comments on this vulnerability, please visit https://discuss.flarum.org/
For support questions, create a discussion at https://discuss.flarum.org/t/support.
A reminder that if you ever become aware of a security issue in Flarum, please report it to us privately by emailing [email protected], and we will address it promptly.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | flarum/core | all versions | 1.8.5 |
| 🐘Packagist | flarum/framework | all versions | 1.8.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for flarum/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 flarum/core to 1.8.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-733r-8xcp-w9mr 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-733r-8xcp-w9mr 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-733r-8xcp-w9mr. 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-733r-8xcp-w9mr in your dependencies?
O3 detects GHSA-733r-8xcp-w9mr across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.