Checkmk up to 2.3.0/2.4.0p39/2.5.0p18 Special Agent argument injection

CVSS Meta Temp Score
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CTI Interest Score
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4.5$0-$5k0.61+

Summaryinfo

A vulnerability was found in Checkmk up to 2.3.0/2.4.0p39/2.5.0p18. It has been declared as problematic. Affected is an unknown function of the component Special Agent. Executing a manipulation can lead to argument injection. This vulnerability is tracked as CVE-2026-121374. The attack can be launched remotely. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Checkmk up to 2.3.0/2.4.0p39/2.5.0p18. It has been declared as problematic. This vulnerability affects some unknown processing of the component Special Agent. The manipulation with an unknown input leads to a argument injection vulnerability. The CWE definition for the vulnerability is CWE-88. The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Argument injection in the Kubernetes special agent in Checkmk <2.5.0p19, <2.4.0p40, and 2.3.0 (EOL) allows a user with permission to edit rules in at least one folder to write files to arbitrary locations writable by the site user via crafted node roles in the "Exclude nodes based on their role" rule option, leading to code execution as the site user.

The advisory is available at checkmk.com. This vulnerability was named CVE-2026-121374 since 11/03/2026. The exploitation appears to be easy. The attack can be initiated remotely. Additional levels of successful authentication are required for exploitation. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1059 by the MITRE ATT&CK project.

Upgrading to version 2.4.0p40 or 2.5.0p19 eliminates this vulnerability.

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Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 4.7
VulDB Meta Temp Score: 4.5

VulDB Base Score: 4.7
VulDB Temp Score: 4.5
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: Argument injection
CWE: CWE-88 / CWE-74 / CWE-707
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: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Checkmk 2.4.0p40/2.5.0p19

Timelineinfo

11/03/2026 CVE reserved
11/11/2026 +8 days Advisory disclosed
11/11/2026 +0 days VulDB entry created
11/11/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: checkmk.com
Status: Confirmed

CNA: Checkmk
CVE: CVE-2026-121374 (🔒)

GCVE (CVE): GCVE-0-2026-121374
GCVE (VulDB): GCVE-100-435742

Entryinfo

Created: 11/11/2026 12:11
Changes: 11/11/2026 12:11 (65)
Complete: 🔍
Cache ID: 216::103

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