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.
Advisories

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Fixes

Solution

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Workaround

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History

Tue, 27 Jan 2026 20:30:00 +0000

Type Values Removed Values Added
First Time appeared Grafana
Grafana grafana
Grafana grafana Enterprise
Vendors & Products Grafana
Grafana grafana
Grafana grafana Enterprise

Tue, 27 Jan 2026 15:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-400
CWE-703
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 27 Jan 2026 09:15:00 +0000

Type Values Removed Values Added
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.
Title Unauthenticated DoS: avatar cache leaks goroutines when /avatar/:hash requests time out
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GRAFANA

Published:

Updated: 2026-01-27T14:29:08.671Z

Reserved: 2026-01-05T09:26:06.214Z

Link: CVE-2026-21720

cve-icon Vulnrichment

Updated: 2026-01-27T14:27:05.963Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-01-27T09:15:48.490

Modified: 2026-01-27T15:15:57.583

Link: CVE-2026-21720

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-01-27T20:17:18Z

Weaknesses