Grafana Loki up to 3.6.x Query Engine allocation of resources

CVSS Meta Temp Score
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CTI Interest Score
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5.1$0-$5k0.44+

Summaryinfo

A vulnerability was found in Grafana Loki up to 3.6.x and classified as problematic. This issue affects some unknown processing of the component Query Engine. Such manipulation leads to allocation of resources. This vulnerability is referenced as CVE-2026-21729. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Grafana Loki up to 3.6.x. Affected by this issue is an unknown code of the component Query Engine. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. CVE summarizes:

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

The advisory is shared for download at grafana.com. This vulnerability is handled as CVE-2026-21729 since 01/05/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 3.7.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-44862). Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Allocation of resources
CWE: CWE-770 / CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: Loki 3.7.0

Timelineinfo

01/05/2026 CVE reserved
07/16/2026 +191 days Advisory disclosed
07/16/2026 +0 days VulDB entry created
07/16/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: grafana.com
Status: Confirmed

CVE: CVE-2026-21729 (🔒)
GCVE (CVE): GCVE-0-2026-21729
GCVE (VulDB): GCVE-100-379460
EUVD: 🔒

Entryinfo

Created: 07/16/2026 05:54
Updated: 07/16/2026 07:10
Changes: 07/16/2026 05:54 (53), 07/16/2026 07:10 (1)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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