Grafana up to 12.3.0 Gravatar Image /avatar/:hash random values

CVSS Meta Temp Score
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CTI Interest Score
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6.3$0-$5k0.00

Summaryinfo

A vulnerability marked as problematic has been reported in Grafana up to 11.6.8/12.0.7/12.1.4/12.2.2/12.3.0. Affected by this vulnerability is an unknown functionality of the file /avatar/:hash of the component Gravatar Image Handler. Performing a manipulation results in random values. This vulnerability is cataloged as CVE-2026-21720. It is possible to initiate the attack remotely. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Grafana up to 11.6.8/12.0.7/12.1.4/12.2.2/12.3.0. It has been classified as problematic. This affects an unknown code of the file /avatar/:hash of the component Gravatar Image Handler. The manipulation with an unknown input leads to a random values vulnerability. CWE is classifying the issue as CWE-330. The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers. This is going to have an impact on availability. The summary by CVE is:

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.

The advisory is shared at grafana.com. This vulnerability is uniquely identified as CVE-2026-21720 since 01/05/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1600.001 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 297198 (Grafana Labs 3.0.0 < 11.6.9+security-01 / 12.0.0 < 12.0.8+security-01 / 12.1.0 < 12.1.5+security-01 / 12.2.0 < 12.2.3+security-01 / 12.3.0 < 12.3.1+security-01 DoS (CVE-2026-21720)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 11.6.9, 12.0.8, 12.1.5, 12.2.3 or 12.3.1 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (297198) and CERT Bund (WID-SEC-2026-0224). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Red Hat Enterprise Linux
  • Oracle Linux
  • RESF Rocky Linux
  • Grafana Grafana

Productinfo

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

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

CNA Base Score: 7.5
CNA Vector (GRAFANA): 🔒

CVSSv2info

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

Exploitinginfo

Class: Random values
CWE: CWE-330 / CWE-310
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 297198
Nessus Name: Grafana Labs 3.0.0 < 11.6.9+security-01 / 12.0.0 < 12.0.8+security-01 / 12.1.0 < 12.1.5+security-01 / 12.2.0 < 12.2.3+security-01 / 12.3.0 < 12.3.1+security-01 DoS (CVE-2026-21720)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Grafana 11.6.9/12.0.8/12.1.5/12.2.3/12.3.1

Timelineinfo

01/05/2026 CVE reserved
01/27/2026 +22 days Advisory disclosed
01/27/2026 +0 days VulDB entry created
03/02/2026 +34 days VulDB entry last update

Sourcesinfo

Advisory: grafana.com
Status: Confirmed

CVE: CVE-2026-21720 (🔒)
GCVE (CVE): GCVE-0-2026-21720
GCVE (VulDB): GCVE-100-342969
CERT Bund: WID-SEC-2026-0224 - Grafana: Mehrere Schwachstellen

Entryinfo

Created: 01/27/2026 10:54
Updated: 03/02/2026 13:33
Changes: 01/27/2026 10:54 (64), 01/27/2026 14:30 (7), 01/30/2026 22:07 (2), 02/18/2026 14:09 (1), 03/02/2026 13:33 (1)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

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