CVE-2023-45820

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);
});

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.

CVE-2023-45820 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (10.6.2); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2023-45820? CVE-2023-45820 is a high-severity security vulnerability in directus (npm), affecting versions >= 10.4.0, < 10.6.2. It is fixed in 10.6.2.
2. How severe is CVE-2023-45820? CVE-2023-45820 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of directus are affected by CVE-2023-45820? directus (npm) versions >= 10.4.0, < 10.6.2 is affected.
4. Is there a fix for CVE-2023-45820? Yes. CVE-2023-45820 is fixed in 10.6.2. Upgrade to this version or later.
5. Is CVE-2023-45820 exploitable, and should I be worried? Whether CVE-2023-45820 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2023-45820 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2023-45820? Upgrade directus to 10.6.2 or later.

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