GHSA-fm53-mpmp-7qw2
HIGHPossible cross-site scripting attack via unsanitized SVG files in FoF Upload
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
fof/uploadReal-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
If FoF Upload is configured to allow the uploading of SVG files (image/svg+xml), navigating directly to an SVG file URI could execute arbitrary Javascript code decided by an attacker.
This Javascript code could include the execution of HTTP web requests to Flarum, or any other web service. This could allow data to be leaked by an authenticated Flarum user, or, possibly, for data to be modified maliciously.
Patches
This has been patched with v1.2.3, which now sanitizes uploaded SVG files.
Workarounds
Upgrade to 1.2.3 (requires Flarum 1.2 or later), or remove the ability for users to upload SVG files through FoF Upload.
References
Thank you to Safwat Refaat for the responsible disclosure of this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | fof/upload | all versions | 1.2.3 |
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 fof/upload. 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 fof/upload to 1.2.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fm53-mpmp-7qw2 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-fm53-mpmp-7qw2 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-fm53-mpmp-7qw2. 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-fm53-mpmp-7qw2 in your dependencies?
O3 detects GHSA-fm53-mpmp-7qw2 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.