CVE-2026-21720 (GCVE-0-2026-21720)

Vulnerability from cvelistv5 – Published: 2026-01-27 09:07 – Updated: 2026-07-07 21:08
VLAI
Title
Unauthenticated DoS: avatar cache leaks goroutines when /avatar/:hash requests time out
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.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-400 - Uncontrolled Resource Consumption
  • CWE-703 - Improper Check or Handling of Exceptional Conditions
  • CWE-772 - Missing Release of Resource after Effective Lifetime
Assigner
References
Impacted products
Vendor Product Version
Grafana grafana/grafana-enterprise Affected: 3.0.0 , < 11.6.9 (semver)
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Grafana grafana/grafana-enterprise Affected: 3.0.0 , < 12.0.8 (semver)
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Grafana grafana/grafana-enterprise Affected: 3.0.0 , < 12.1.5 (semver)
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Grafana grafana/grafana Affected: 3.0.0 , < 11.6.9 (semver)
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Grafana grafana/grafana Affected: 3.0.0 , < 12.0.8 (semver)
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Grafana grafana/grafana Affected: 3.0.0 , < 12.1.5 (semver)
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Grafana grafana/grafana-enterprise Affected: 3.0.0 , < 12.2.3 (semver)
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Grafana grafana/grafana Affected: 3.0.0 , < 12.2.3 (semver)
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Grafana grafana/grafana-enterprise Affected: 3.0.0 , < 12.3.1 (semver)
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Grafana grafana/grafana Affected: 3.0.0 , < 12.3.1 (semver)
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Red Hat Red Hat Ceph Storage 7     cpe:/a:redhat:ceph_storage:7
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Red Hat Red Hat Ceph Storage 8     cpe:/a:redhat:ceph_storage:8
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Red Hat Red Hat Enterprise Linux 10     cpe:/o:redhat:enterprise_linux:10
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Red Hat Red Hat Enterprise Linux 8     cpe:/o:redhat:enterprise_linux:8
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Red Hat Red Hat Enterprise Linux 9     cpe:/o:redhat:enterprise_linux:9
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Date Public
2026-01-27 09:03
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}



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Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.