CVE-2023-43645
MEDIUMCVE-2023-43645 is a medium-severity (CVSS 5.9) CWE-835 vulnerability in github.com/openfga/openfga. O3 Security confirms whether CVE-2023-43645 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Denial of service from circular relationship definitions in OpenFGA
Blast Radius
github.com/openfga/openfgaReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
OpenFGA is an authorization/permission engine built for developers and inspired by Google Zanzibar. OpenFGA is vulnerable to a denial of service attack when certain Check calls are executed against authorization models that contain circular relationship definitions. When the call is made, it's possible for the server to exhaust resources and die. Users are advised to upgrade to v1.3.2 and update any offending models. There are no known workarounds for this vulnerability. Note that for models which contained cycles or a relation definition that has the relation itself in its evaluation path, checks and queries that require evaluation will no longer be evaluated on v1.3.2+ and will return errors instead. Users who do not have cyclic models are unaffected.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/openfga/openfga | all versions | 1.3.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/openfga/openfga. 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 github.com/openfga/openfga to 1.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-43645 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 CVE-2023-43645 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 CVE-2023-43645. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-43645 in your dependencies?
O3 detects CVE-2023-43645 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.