CVE-2026-21720

Summary

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.

Affected Software

VendorProductVersion RangeStatus
Grafanagrafana/grafana-enterprise3.0.0 < 11.6.9affected
Grafanagrafana/grafana-enterprise3.0.0 < 12.0.8affected
Grafanagrafana/grafana-enterprise3.0.0 < 12.1.5affected
Grafanagrafana/grafana3.0.0 < 11.6.9affected
Grafanagrafana/grafana3.0.0 < 12.0.8affected
Grafanagrafana/grafana3.0.0 < 12.1.5affected
Grafanagrafana/grafana-enterprise3.0.0 < 12.2.3affected
Grafanagrafana/grafana3.0.0 < 12.2.3affected
Grafanagrafana/grafana-enterprise3.0.0 < 12.3.1affected
Grafanagrafana/grafana3.0.0 < 12.3.1affected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

grafana: Grafana: Denial of Service via resource exhaustion from avatar requests

Additional References

References