Riskcovery

CVE-2026-21720

Unauthenticated DoS: avatar cache leaks goroutines when /avatar/:hash requests time out

State
Published
Severity
7.5 High
Published
Jan 27, 2026
Updated
Aug 27, 2026
Reserved
Jan 5, 2026

Read the record on cve.org

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.

Scores

CVSSScoreVectorSource
3.17.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HGRAFANA
3.17.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hredhat-SADP

Weaknesses

  • CWE-400 Uncontrolled Resource Consumption
  • CWE-703 Improper Check or Handling of Exceptional Conditions
  • CWE-772 Missing Release of Resource after Effective Lifetime

Affected Products

ProductVersions
grafana/grafana-enterpriseGrafana
  • 3.0.0 to before 11.6.9Affected
grafana/grafana-enterpriseGrafana
  • 3.0.0 to before 12.0.8Affected
grafana/grafana-enterpriseGrafana
  • 3.0.0 to before 12.1.5Affected
grafana/grafanaGrafana
  • 3.0.0 to before 11.6.9Affected
grafana/grafanaGrafana
  • 3.0.0 to before 12.0.8Affected
grafana/grafanaGrafana
  • 3.0.0 to before 12.1.5Affected
grafana/grafana-enterpriseGrafana
  • 3.0.0 to before 12.2.3Affected
grafana/grafanaGrafana
  • 3.0.0 to before 12.2.3Affected
grafana/grafana-enterpriseGrafana
  • 3.0.0 to before 12.3.1Affected
grafana/grafanaGrafana
  • 3.0.0 to before 12.3.1Affected

References

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