GHSA-4gm4-c4mh-4p7w
MEDIUMFirefly III has a MFA bypass in oauth flow
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
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
Impact
A MFA bypass in the Firefly III OAuth flow may allow malicious users to bypass the MFA-check. This allows malicious users to use password spraying to gain access to your Firefly III data using passwords stolen from other sources. As OAuth applications are easily enumerable using an incrementing id, an attacker could try sign an OAuth application up to a users profile quite easily if they have created one. The attacker would also need to know the victims username and password.
Patches
Problem has been patched in Firefly III v6.1.17 and up.
Workarounds
- Use a unique password for your Firefly III instance,
- Store your password securely, i.e. in a password manager or in your head.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | grumpydictator/firefly-iii | all versions | 6.1.17 |
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. 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 grumpydictator/firefly-iii to 6.1.17 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4gm4-c4mh-4p7w 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-4gm4-c4mh-4p7w 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-4gm4-c4mh-4p7w. 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-4gm4-c4mh-4p7w in your dependencies?
O3 detects GHSA-4gm4-c4mh-4p7w across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.