CVE-2026-21720— Unauthenticated DoS: avatar cache leaks goroutines when /avatar/:hash requests time out
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I. Basic Information for CVE-2026-21720
Vulnerability Information
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Vulnerability Title
Unauthenticated DoS: avatar cache leaks goroutines when /avatar/:hash requests time out
Source: NVD (National Vulnerability Database)
Vulnerability Description
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.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Grafana 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Grafana是Grafana开源的一套提供可视化监控界面的开源监控工具。该工具主要用于监控和分析Graphite、InfluxDB和Prometheus等。 Grafana存在安全漏洞，该漏洞源于处理随机哈希的/avatar/:hash请求时，goroutine可能无限增长并阻塞，最终耗尽内存导致崩溃。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Grafana | grafana/grafana-enterprise | 3.0.0 ~ 11.6.9 | - | |
| Grafana | grafana/grafana-enterprise | 3.0.0 ~ 12.0.8 | - | |
| Grafana | grafana/grafana-enterprise | 3.0.0 ~ 12.1.5 | - | |
| Grafana | grafana/grafana | 3.0.0 ~ 11.6.9 | - | |
| Grafana | grafana/grafana | 3.0.0 ~ 12.0.8 | - | |
| Grafana | grafana/grafana | 3.0.0 ~ 12.1.5 | - | |
| Grafana | grafana/grafana-enterprise | 3.0.0 ~ 12.2.3 | - | |
| Grafana | grafana/grafana | 3.0.0 ~ 12.2.3 | - | |
| Grafana | grafana/grafana-enterprise | 3.0.0 ~ 12.3.1 | - | |
| Grafana | grafana/grafana | 3.0.0 ~ 12.3.1 | - |
II. Public POCs for CVE-2026-21720
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|---|
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IV. Related Vulnerabilities
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V. Comments for CVE-2026-21720
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