CVE-2026-21729

Loki detected_fields query limits results in unbounded memory allocation

7.5 High

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

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

0.46%Up 0.2 points since Jul 16, 2026

What each source reports

CVE List Score used 7.5

Loki detected_fields query limits results in unbounded memory allocation

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

Record: CVE-2026-21729
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-770
Updated: 2026-11-02

EUVDEUVD-2026-44862 7.5

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

Record: EUVD-2026-44862
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

GitHub AdvisoriesGHSA-65p5-8cm9-qcxx 7.5

Loki queries with large limits can cause large memory allocations which can impact the...

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

Record: GHSA-65p5-8cm9-qcxx
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-770
Updated: 2026-11-02

NVD 7.5

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

Record: CVE-2026-21729
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-770
Updated: 2026-11-02

OSVRHSA-2026:72570 7.5

Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

Record: RHSA-2026:72570
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

Affected products

grafana loki

Affected packages

Affected packages
Package	Affected	Fixed
`loki3.6` Red Hat:hummingbird:1 From an advisory covering 5 CVEs	before 0:3.6.17-0.3.hum1	0:3.6.17-0.3.hum1
`loki3.6-canary` Red Hat:hummingbird:1 From an advisory covering 5 CVEs	before 0:3.6.17-0.3.hum1	0:3.6.17-0.3.hum1
`loki3.6-logcli` Red Hat:hummingbird:1 From an advisory covering 5 CVEs	before 0:3.6.17-0.3.hum1	0:3.6.17-0.3.hum1

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected, facts
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-21729 is a high vulnerability (CVSS 7.5) in Grafana Loki, published July 16, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.46%, the 40th percentile. No source names a fixed version.

References

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