CVE-2023-45820 is a medium-severity (CVSS 5.9) CWE-755 vulnerability in directus. 1 public exploit reference exists, so weaponization risk is real. A fix is available for directus — see the affected versions and patch details below.
Directus crashes on invalid WebSocket message
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-2023-45820.
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.
How urgent is this, really
CVE-2023-45820 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
directusnpmDescription
Summary
It seems that any Directus installation that has websockets enabled can be crashed if the websocket server receives an invalid frame. This could probably be posted as an issue and I might even be able to put together a pull request for a fix (if only I had some extra time...), but I decided to instead post as a vulnerability just for the maintainers, since this seemingly can be used to crash any live Directus server if websockets are enabled, so public disclosure is not a good idea until the issue is fixed.
Details
The fix for this seems quite simple; the websocket server just needs to properly catch the error instead of crashing the server. See for example: https://github.com/websockets/ws/issues/2098
PoC
- Start a fresh Directus server (using for example the compose file here: https://docs.directus.io/self-hosted/docker-guide.html). Enable websockets by setting
WEBSOCKETS_ENABLED: 'true'environment variable. - run a separate node app somewhere else to send an invalid frame to the server:
const WebSocket = require("ws");
const websocket = new WebSocket("ws://0.0.0.0:8055/websocket");
websocket.on("open", function () {
const chunk = Buffer.from("a180", "hex");
websocket._socket.write(chunk);
});
Impact
The server crashes with an error: RangeError: Invalid WebSocket frame: RSV2 and RSV3 must be clear. Server needs to be manually restarted to get back online (if there's no recovery mechanism in place, as there often isn't with simple node servers). This was confirmed on a local server, and additionally I was able to crash our staging server with the same code, just pointing to our staging Directus server running at fly.io. It seems to also crash servers running in the directus.cloud service. I created https://websocket-test.directus.app/, pointed the above script to the websocket url of that instance and the server does crash for a while. It seems that in there there's a mechanism for bringing the server back up quite fast, but it would be quite trivial for anyone to DoS any server running in directus.cloud by just spamming these invalid frames to the server.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | directus | ≥ 10.4.0&&< 10.6.2 | 10.6.2npm install directus@10.6.2 |
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 directus, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update directus to 10.6.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-45820 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-45820 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-45820. 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-2023-45820 in your dependencies?
O3 Security finds CVE-2023-45820 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.