CVE-2026-21720
Unauthenticated DoS: avatar cache leaks goroutines when /avatar/:hash requests time out
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
5th
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.
| Vendor | grafana |
| Product | grafana/grafana-enterprise |
| Ecosystems | |
| Industries | Technology |
| Published | Jan 27, 2026 |
| Last Updated | Apr 15, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
Affected Versions
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