CVE-2025-3454 is a medium-severity vulnerability affecting Grafana versions 10.4.0 through 11.6.0. The flaw resides in Grafana's datasource proxy API, specifically in the way it handles authorization checks for certain GET endpoints related to Alertmanager and Prometheus datasources. The vulnerability allows an attacker with minimal permissions to bypass authorization by manipulating the URL path with an extra slash character. This bypass enables unauthorized read access to sensitive data exposed by these endpoints. The issue is rooted in improper enforcement of route-specific permissions (CWE-285: Improper Authorization), which are intended to restrict access based on user privileges. Since the vulnerability affects datasources that implement route-specific permissions, it primarily impacts Alertmanager and Prometheus-based datasources integrated into Grafana. The vulnerability does not require user interaction and can be exploited remotely over the network (CVSS vector: AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N). The scope is changed (S:C) because the vulnerability allows access beyond the originally authorized scope, impacting confidentiality but not integrity or availability. No known exploits are currently reported in the wild, and no patches have been linked yet. However, the vulnerability's presence in widely used Grafana versions makes it a significant concern for organizations relying on these monitoring tools.

For European organizations, this vulnerability poses a risk to the confidentiality of monitoring and alerting data managed through Grafana, particularly when using Alertmanager and Prometheus datasources. Unauthorized read access could expose sensitive operational metrics, alert configurations, and potentially security-related information that could aid attackers in reconnaissance or further attacks. Organizations in sectors such as finance, healthcare, energy, and critical infrastructure that rely heavily on Grafana for monitoring may face increased risk of data leakage. The vulnerability could also undermine trust in monitoring systems and complicate incident response efforts. Since Grafana is often deployed in cloud environments and on-premises, the impact spans multiple deployment models common in Europe. The medium severity rating suggests that while the vulnerability is not immediately critical, it should be addressed promptly to prevent potential escalation or exploitation in combination with other vulnerabilities.

European organizations should implement the following specific mitigations: 1) Immediately audit Grafana installations to identify affected versions (10.4.0 through 11.6.0) and prioritize upgrades to patched versions once available. 2) Until patches are released, restrict access to Grafana instances to trusted networks and users, employing network segmentation and firewall rules to limit exposure. 3) Review and tighten datasource permissions, ensuring that users have the minimal necessary privileges and that route-specific permissions are correctly configured. 4) Implement web application firewalls (WAFs) or reverse proxies capable of normalizing URL paths to prevent exploitation via URL path manipulation (extra slash). 5) Monitor Grafana logs for unusual access patterns or attempts to exploit URL path manipulations. 6) Coordinate with Grafana vendors or community channels to obtain patches or workarounds as soon as they become available. 7) Educate administrators and users about the vulnerability to avoid inadvertent exposure or misconfiguration.