CVE-2025-58121VulnerabilityPublished 18 Nov 2025

CVE-2025-58121: Checkmk · Improper Handling of Insufficient Permissions or Privileges

Affects CheckmkSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score

5.3Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% 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:L/VA:L/SC:N/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: Low
Vulnerable system availability: Low
Subsequent system confidentiality: None
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: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
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 Nov 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 2026-10-26.

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 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 =2.2.0	Fixed in–

AI-suggested

1. Apply patches or updates from Checkmk GmbH as soon as they become available, specifically versions beyond 2.4.0p16 where the vulnerability is fixed. 2. Until patches are deployed, restrict access to Checkmk REST API endpoints by implementing network segmentation and firewall rules that limit API access to trusted management networks or specific IP addresses. 3. Enforce strict role-based access control (RBAC) within Checkmk to minimize the privileges assigned to users, ensuring that low-privileged accounts cannot access sensitive API functions. 4. Monitor API usage logs for unusual or unauthorized requests that could indicate exploitation attempts, and integrate these logs into a centralized security information and event management (SIEM) system for real-time alerting. 5. Conduct regular security audits and penetration tests focusing on API security to identify and remediate permission validation issues proactively. 6. Educate administrators and users about the risks of improper API access and the importance of credential hygiene to prevent unauthorized access. 7. Consider deploying web application firewalls (WAFs) or API gateways with fine-grained access controls and anomaly detection to provide an additional layer of defense.

Description

Insufficient permission validation on multiple REST API endpoints in Checkmk 2.2.0, 2.3.0, and 2.4.0 before version 2.4.0p16 allows low-privileged users to perform unauthorized actions or obtain sensitive information

Impact

For European organizations, the impact of CVE-2025-58121 can be significant depending on the deployment scale and criticality of Checkmk in their IT environments. Unauthorized access to REST API endpoints can lead to exposure of sensitive monitoring data, including system health, network status, and potentially credentials or configuration details. This information leakage can facilitate further attacks such as lateral movement, privilege escalation, or targeted disruption of IT operations. Additionally, unauthorized actions performed via the API could alter monitoring configurations or suppress alerts, undermining the integrity and availability of monitoring services. Such disruptions can delay incident detection and response, increasing the risk of prolonged outages or data breaches. Industries with stringent compliance requirements, such as finance, healthcare, and critical infrastructure sectors across Europe, may face regulatory and reputational consequences if this vulnerability is exploited. The medium severity rating reflects a balance between the ease of exploitation and the limited but meaningful impact on confidentiality, integrity, and availability. Since Checkmk is popular in Germany and other EU countries for IT monitoring, the threat is particularly relevant to organizations in these regions.

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/18983 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Nov 2025, 16:21 UTC

WeaknessesCWE-280

Technical details

References

Community reviews

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