CVE-2022-39229 is a medium-severity authentication vulnerability affecting Grafana, an open-source platform widely used for data visualization of metrics, logs, and traces. The flaw exists in Grafana versions 8.5.0 through 8.5.13 and 9.0.0 through 9.1.7. The vulnerability arises from the way Grafana handles usernames and email addresses during login. Both usernames and email addresses are unique identifiers in Grafana, and users can log in using either their username or email address. However, the system allows a user to register a username that matches another user's email address. For example, if user_1 has an email address user1@example.com, another user (user_2) can register their username as user1@example.com. This causes a conflict during login because the authentication system attempts to match the login identifier to a single user record. When user_1 tries to log in using their email address, the system associates the login attempt with user_2's account, causing the login to fail since the password does not match. This effectively allows user_2 to block user_1 from logging in by registering a username identical to user_1's email address. The vulnerability is classified under CWE-287 (Improper Authentication) because it allows an attacker to disrupt the authentication process without needing to know the victim's password or credentials. The issue was patched in Grafana versions 9.1.8 and 8.5.14. No workarounds exist, so upgrading to these or later versions is necessary to remediate the vulnerability. There are no known exploits in the wild as of the published date, and the vulnerability does not require user interaction or elevated privileges to exploit, only the ability to register a Grafana account. The impact is primarily denial of service at the user authentication level, preventing legitimate users from accessing their accounts.

For European organizations using vulnerable versions of Grafana, this vulnerability can lead to denial of service for individual users by blocking their login attempts. This can disrupt monitoring, alerting, and visualization workflows critical for IT operations, security monitoring, and business intelligence. In environments where Grafana dashboards are used for operational decision-making or security incident response, such disruptions could delay detection and response to incidents, increasing risk exposure. The vulnerability does not directly expose sensitive data or allow privilege escalation, but the denial of service could be leveraged by malicious insiders or external attackers with account registration capabilities to cause operational disruptions. Organizations with large user bases or multi-tenant Grafana deployments are at higher risk since attackers can register usernames matching multiple users' email addresses to block access at scale. The lack of known exploits reduces immediate risk, but the ease of exploitation and absence of workarounds mean that vulnerable systems remain exposed until patched. Given Grafana's popularity in European public sector, finance, manufacturing, and telecommunications sectors, the operational impact could be significant if exploited.

The only effective mitigation is to upgrade all affected Grafana instances to version 9.1.8 or 8.5.14 or later, where the vulnerability is patched. Organizations should prioritize patching in environments where user access disruptions would have the greatest operational impact. Additionally, organizations should audit user registrations to detect any usernames that match existing users' email addresses and remediate by renaming or removing conflicting accounts post-patch. Implementing strict user registration policies and monitoring for suspicious account creation activity can help detect attempts to exploit this vulnerability. For environments where immediate patching is not feasible, restricting user registration to trusted personnel or integrating Grafana with centralized authentication providers (e.g., LDAP, OAuth) that enforce unique identifiers can reduce risk. Finally, organizations should review their incident response plans to include scenarios involving denial of service on monitoring platforms and ensure alternative monitoring access methods are available.