CVE-2026-21720

A flaw was found in Grafana. A remote attacker can exploit this vulnerability by sending a sustained volume of uncached /avatar/:hash requests. This action causes the system to create and block goroutines, which are lightweight concurrent functions, leading to a continuous increase in memory usage. Over time, this resource exhaustion can cause Grafana to crash, resulting in a Denial of Service (DoS).

This IMPORTANT denial of service vulnerability in Grafana allows an unauthenticated attacker to exhaust system resources. By sending sustained requests to the /avatar/:hash endpoint, goroutines leak due to timed-out Gravatar image refreshes, leading to memory exhaustion and potential Grafana service crashes. This affects Grafana instances shipped with Red Hat Ceph Storage, Red Hat Enterprise Linux, and Red Hat In-Vehicle OS.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.