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)
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.007 (51.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 51.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.007 · change: +0.001
Affected products
- Grafana — versions 12.3.0
- Grafana Grafana/grafana — versions 3.0.0
- Grafana Grafana/grafana-Enterprise — versions 3.0.0
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.