Resource exhaustion in Grafana

CVE-2026-21720

Every uncached /avatar/:hash request spawns a goroutine that refreshes the Gravatar image. If the refresh sits in the 10-slot worker queue longer than three seconds, the handler times out and stops listening for the result, so that goroutine blocks forever trying to send on an unbuffered channel. Sustained traffic with random hashes keeps tripping this timeout, so goroutine count grows linearly, eventually exhausting memory and causing Grafana to crash on some systems.

Vulnerability class: DoS (Denial of Service)

EPSS: 0.006 (46.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-21720?
CVE-2026-21720 is a high-severity vulnerability in Grafana, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-01-27.
How severe is CVE-2026-21720?
High severity. CVSS v3 base score is 7.5 out of 10.