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Fencer Vulns
high 7.5

CVE-2026-21728 json

Tempo query limit results in unbounded memory allocation

published 2026-04-24 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-25408 , GHSA-p4r4-xvrq-gvmc , GO-2026-5528

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits
0
none known

Summary

Tempo queries with large limits can cause large memory allocations which can impact the availability of the service, depending on its deployment strategy.

Mitigation can be done by setting max_result_limit in the search config, e.g. to 262144 (2^18). Alternatively, automatically restart the service.

Patch / fix

  • go github.com/grafana/tempo 2.8.4, 2.9.2, 2.10.2
  • Red Hat Multicluster Global Hub 1.3.4 1779212259
  • Red Hat Multicluster Global Hub 1.4.5 1779579439
  • Red Hat Multicluster Global Hub 1.6.5 1780167118
  • Red Hat Multicluster Global Hub 1.7.0 1779925273
  • Red Hat Red Hat multicluster global hub 1.5.3 1778867753
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-21728 updated cvss 7.5

grafana/tempo: Tempo: Denial of Service via large queries

  • Red Hat Ceph Storage 5 rhceph/rhceph-5-dashboard-rhel8 Red Hat Ceph Storage 6 rhceph/rhceph-6-dashboard-rhel9 Red Hat Ceph Storage 9 rhceph/grafana-rhel10 Red Hat OpenShift distributed tracing 3 rhosdt/tempo-gateway-rhel9
    affected: no fix available
  • Red Hat Multicluster Global Hub 1.3.4 multicluster-globalhub/multicluster-globalhub-grafana-rhel9 1779212259
    fixed: vendor fix RHSA-2026:22423
  • Red Hat Multicluster Global Hub 1.4.9 multicluster-globalhub/multicluster-globalhub-grafana-rhel9 1779579439
    fixed: vendor fix RHSA-2026:22347
  • Red Hat Multicluster Global Hub 1.5.8 multicluster-globalhub/multicluster-globalhub-grafana-rhel9 1778867753
    fixed: vendor fix RHSA-2026:21769
  • Red Hat Multicluster Global Hub 1.6.6 multicluster-globalhub/multicluster-globalhub-grafana-rhel9 1780167118
    fixed: vendor fix RHSA-2026:23345
  • Red Hat Multicluster Global Hub 1.7.3 multicluster-globalhub/multicluster-globalhub-grafana-rhel9 1779925273
    fixed: vendor fix RHSA-2026:24503
  • Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/lokistack-gateway-rhel9
    not affected: component not present
  • Red Hat Multicluster Global Hub multicluster-globalhub/multicluster-globalhub-grafana-rhel8 Red Hat Multicluster Global Hub 1.3.4 multicluster-globalhub/multicluster-globalhub-agent-rhel9 1779210675, multicluster-globalhub/multicluster-globalhub-manager-rhel9 1779210608, multicluster-globalhub/multicluster-globalhub-rhel9-operator 1779209992, multicluster-globalhub/multicluster-globalhub-operator-bundle 1779925031, multicluster-globalhub/multicluster-globalhub-postgres-exporter-rhel9 1779924243 Red Hat Multicluster Global Hub 1.4.9 multicluster-globalhub/multicluster-globalhub-agent-rhel9 1779838819, multicluster-globalhub/multicluster-globalhub-manager-rhel9 1779839447, multicluster-globalhub/multicluster-globalhub-rhel9-operator 1779887217, multicluster-globalhub/multicluster-globalhub-operator-bundle 1779891163, multicluster-globalhub/multicluster-globalhub-postgres-exporter-rhel9 1779147132 Red Hat Multicluster Global Hub 1.5.8 multicluster-globalhub/multicluster-globalhub-agent-rhel9 1779828691, multicluster-globalhub/multicluster-globalhub-manager-rhel9 1779828813, multicluster-globalhub/multicluster-globalhub-rhel9-operator 1779828536, multicluster-globalhub/multicluster-globalhub-operator-bundle 1779837290, multicluster-globalhub/multicluster-globalhub-postgres-exporter-rhel9 1779835152 Red Hat Multicluster Global Hub 1.6.6 multicluster-globalhub/multicluster-globalhub-agent-rhel9 1780320809, multicluster-globalhub/multicluster-globalhub-manager-rhel9 1780321673, multicluster-globalhub/multicluster-globalhub-rhel9-operator 1779839087, multicluster-globalhub/multicluster-globalhub-operator-bundle 1780370487, multicluster-globalhub/multicluster-globalhub-postgres-exporter-rhel9 1779839762 Red Hat Multicluster Global Hub 1.7.3 multicluster-globalhub/multicluster-globalhub-agent-rhel9 1780361828, multicluster-globalhub/multicluster-globalhub-manager-rhel9 1780615638, multicluster-globalhub/multicluster-globalhub-rhel9-operator 1779887500, multicluster-globalhub/multicluster-globalhub-operator-bundle 1780616828, multicluster-globalhub/multicluster-globalhub-postgres-exporter-rhel9 1779815431
    not affected: vulnerable code not present
show 2 more
  • Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/acm-grafana-rhel9
    not affected: component not present
  • Red Hat Enterprise Linux 9 grafana, grafana-selinux Red Hat Enterprise Linux 10 grafana Red Hat OpenShift distributed tracing 3 rhosdt/tempo-rhel9, rhosdt/tempo-query-rhel9, rhosdt/tempo-rhel9-operator
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.64% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
go github.com/grafana/tempo
>=1.3.0, <2.8.4
>=2.9.0, <2.9.2
>=2.10.0, <2.10.2
>=1.3.0
2.8.4
2.9.2
2.10.2

Affected products

  • Grafana Tempo
  • Grafana Enterprise Traces (GET)
  • Red Hat Multicluster Global Hub 1.3.4
  • Red Hat Multicluster Global Hub 1.4.5
  • Red Hat Multicluster Global Hub 1.6.5
  • Red Hat Multicluster Global Hub 1.7.0
  • Red Hat Red Hat multicluster global hub 1.5.3
  • Red Hat Logging Subsystem for Red Hat OpenShift
  • Red Hat Multicluster Global Hub
  • Red Hat Red Hat Advanced Cluster Management for Kubernetes 2
  • Red Hat Red Hat Ceph Storage 5
  • Red Hat Red Hat Ceph Storage 6
  • Red Hat Red Hat Ceph Storage 9
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat OpenShift distributed tracing 3

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.