CVE-2023-35933 is a medium-severity (CVSS 5.9) CWE-835 vulnerability in github.com/openfga/openfga. 2 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for github.com/openfga/openfga — see the affected versions and patch details below.
OpenFGA denial of service die to circular relationship
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-35933.
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
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
Overview
OpenFGA versions v1.1.0 and prior are vulnerable to a DoS attack when certain Check and ListObjects calls are executed against authorization models that contain circular relationship definitions.
Am I Affected?
You are affected by this vulnerability if you are using OpenFGA v1.1.0 or earlier, and if you are executing certain Check or ListObjects calls against a vulnerable authorization model. To see which of your models could be vulnerable to this attack, download OpenFGA v1.2.0 and run the following command:
./openfga validate-models --datastore-engine <ENGINE> --datastore-uri <URI> | jq .[] | select(.Error | contains("loop"))
replacing the variables <ENGINE> and <URI> as needed.
Fix
Upgrade to v1.1.1.
Backward Compatibility
If you are not passing an invalid authorization model (as identified by running ./openfga validate-models) as a parameter of your Check and ListObjects calls, this upgrade is backwards compatible.
Otherwise, OpenFGA v1.1.1 will start returning HTTP 400 status codes on those calls.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/openfga/openfga | all versions | 1.1.1go get github.com/openfga/openfga@v1.1.1 |
Affected Products
openfgaopenfgaResearch 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 github.com/openfga/openfga, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/openfga/openfga to 1.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-35933 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Frequently Asked Questions
Is CVE-2023-35933 in your dependencies?
Find it across Go, including transitive dependencies.