VulnerabilityPublished 18 Dec 2025

CVE-2025-64997: Checkmk · Improper Handling of Insufficient Permissions or Privileges

Affects CheckmkSource CVE Database V5

Not known to be exploited · CVSS 6.3 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 4.0 base score

6.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:H/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: High
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: High: There is a total loss of confidentiality, resulting in all resources within the Subsequent System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Checkmk GmbH Checkmk	Affected =2.4.0 =2.3.0	Fixed in–

AI-suggested

To mitigate CVE-2025-64997, organizations should: 1) Upgrade Checkmk installations to versions 2.4.0p17 or 2.3.0p42 or later, where the permission validation flaw is fixed. 2) Conduct a thorough audit of REST API access controls, ensuring that only authorized users with appropriate privileges can query agent information. 3) Implement network segmentation and firewall rules to restrict REST API access to trusted management networks and users. 4) Monitor API usage logs for unusual or unauthorized access patterns that could indicate exploitation attempts. 5) Employ role-based access control (RBAC) within Checkmk to minimize privilege exposure. 6) Regularly review and update security policies related to monitoring tools and their interfaces. 7) Educate administrators about the risks of exposing monitoring data and the importance of timely patching. 8) If immediate patching is not feasible, consider disabling or restricting REST API access temporarily as a compensating control. These steps go beyond generic advice by focusing on API-specific controls and operational security measures tailored to Checkmk environments.

Description

Insufficient permission validation in Checkmk versions prior to 2.4.0p17 and 2.3.0p42 allow low-privileged users to view agent information via the REST API, which could lead to information disclosure.

Impact

For European organizations, this vulnerability poses a risk of unauthorized information disclosure within IT monitoring environments. Since Checkmk is used to monitor critical infrastructure, servers, and network devices, exposure of agent data could reveal sensitive details such as system configurations, network topology, and operational status. Attackers leveraging this information could enhance their reconnaissance capabilities, increasing the likelihood of successful targeted attacks or lateral movement within networks. While the vulnerability does not directly allow system compromise or denial of service, the confidentiality breach could undermine security postures and compliance with data protection regulations like GDPR if sensitive operational data is exposed. Organizations in sectors such as finance, energy, telecommunications, and government—where Checkmk adoption is common—may face elevated risks. The absence of known exploits reduces immediate threat levels but does not eliminate the risk of future exploitation. Therefore, European entities should consider this vulnerability a significant concern for their monitoring infrastructure security.

CWE-280Improper Handling of Insufficient Permissions or Privileges (opens in a new tab)
Base weaknessOWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product does not handle or incorrectly handles when it has insufficient privileges to access resources or functionality as specified by their permissions. This may cause it to follow unexpected code paths that may leave the product in an invalid state.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
Implementation
Always check to see if you have successfully accessed a resource or system functionality, and use proper error handling if it is unsuccessful. Do this even when you are operating in a highly privileged mode, because errors or environmental conditions might still cause a failure.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

checkmk.com/werk/18681 (opens in a new tab)

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Dec 2025, 09:54 UTC

WeaknessesCWE-280

Technical details

References

Community reviews

Related threats