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CVE Record

CVE-2026-21728: Tempo query limit results in unbounded memory allocation

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).

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-21728 is an availability risk in Grafana Tempo. Large query limits can trigger very large memory allocations, potentially degrading or taking down the service depending on deployment design.

Executive priority

Treat as high priority where Tempo supports production observability or incident response. The main business risk is service disruption, not data theft based on the provided sources.

Technical view

The source describes unbounded memory allocation from Tempo queries using large limits. CVSS 3.1 is 7.5 with network, low-complexity, unauthenticated availability impact and no confidentiality or integrity impact.

Likely exposure

Organizations running Grafana Tempo v1.3.0 are the identified affected group. Exposure is higher where Tempo query access is reachable and search limits are not capped.

Exploitation context

The bundle does not show CISA KEV listing or cited active exploitation. The CVSS vector indicates remote, unauthenticated, low-complexity availability impact, but no exploit activity is evidenced here.

Researcher notes

Evidence is strongest for resource exhaustion in Tempo v1.3.0 with large query limits. The bundle names a configuration mitigation, but does not provide complete affected-version ranges or exploit observations.

Mitigation direction

  • Set search max_result_limit as advised, for example 262144.
  • Check Grafana’s advisory for version-specific remediation guidance.
  • Review Red Hat errata if using Red Hat-packaged Tempo components.
  • Restrict unnecessary network access to Tempo query interfaces.
  • Monitor memory pressure and OOM events around query activity.

Validation and detection

  • Inventory Tempo deployments and confirm whether v1.3.0 is present.
  • Inspect Tempo search configuration for max_result_limit.
  • Verify query interfaces are not unnecessarily internet-exposed.
  • Review logs and metrics for large-limit queries and memory exhaustion.
  • Track Grafana and Red Hat advisory updates for fixed package details.
Prepared
Confidence
medium
Sources
11

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-400: Exact CWE lookup

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cwe · low confidence lookup

CWE-770: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2026-21728 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
10Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6GRAFANA
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-21728Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPgrafana/tempo: Tempo: Denial of Service via large queries
other:Red Hat severity ratingcvssV3_1
  • 2026-04-24T09:00:58.144Z: Reported to Red Hat.
  • 2026-04-24T08:00:47.074Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
GrafanaTempov1.3.0unaffected
Weakness

CWE details

CWE-400CWE-770

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.