Firefly III vulnerable to image-based stored XSSGHSA-pcxq-28f6-m3fm
MEDIUMFix: firefly-iii/firefly-iii@531161dGHSA-pcxq-28f6-m3fm is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in grumpydictator/firefly-iii. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for grumpydictator/firefly-iii — see the affected versions and patch details below.
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
grumpydictator/firefly-iiiReal-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
Firefly III before 4.7.17.3 is vulnerable to stored XSS due to lack of filtration of user-supplied data in image file content. The JavaScript code is executed during attachments/view/$file_id$ attachment viewing. NOTE: It is asserted that an attacker must have the same access rights as the user in order to be able to execute the vulnerability
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | grumpydictator/firefly-iii | all versions | 4.7.17.3composer require grumpydictator/firefly-iii:^4.7.17.3 |
Affected Products
firefly iiifirefly-iiiResearch 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 grumpydictator/firefly-iii, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update grumpydictator/firefly-iii to 4.7.17.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pcxq-28f6-m3fm is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is GHSA-pcxq-28f6-m3fm in your dependencies?
Find it across Packagist, including transitive dependencies.