VulnerabilityPublished 4 Mar 2026

CVE-2026-3103: Checkmk · Incorrect Authorization

Affects CheckmkSource CVE Database V5

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Not known to be exploited · CVSS 5.3 Medium : upgrade to 2.4.0p23 or 2.3.0p43 when convenient.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 4.0 base score

5.3Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.4.0p23, 2.3.0p43

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/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: None
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: None: There is no loss of confidentiality within 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 4 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 29 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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

Upgrade Checkmk to 2.4.0p23 or 2.3.0p43.

Affected software

Product	Affected	Fixed in
Checkmk GmbHCheckmk	Affected >=2.4.0 <2.4.0p23 >=2.3.0 <2.3.0p43 =2.2.0	Fixed in 2.4.0p23 2.3.0p43

AI-suggested

2) Until patches are applied, restrict low-privileged user accounts from accessing or invoking the remove_password() function or related password management features. This can be done by tightening role-based access controls and auditing user permissions. 3) Implement monitoring and alerting on password removal or modification activities within Checkmk logs to detect suspicious behavior early. 4) Employ network segmentation to limit exposure of Checkmk management interfaces to trusted administrators only. 5) Conduct regular reviews of user privileges to ensure no unnecessary low-privileged accounts have access to sensitive functions. 6) Consider deploying application-layer firewalls or intrusion detection systems that can detect anomalous API calls or commands related to password removal. These steps go beyond generic patching advice by focusing on access control hardening and proactive detection to reduce exploitation risk before patches are applied.

Description

A logic error in the remove_password() function in Checkmk GmbH's Checkmk versions <2.4.0p23, <2.3.0p43, and 2.2.0 (EOL) allows a low-privileged user to cause data loss.

Impact

The primary impact of CVE-2026-3103 is the potential for data loss within Checkmk monitoring environments. Since Checkmk is used to monitor IT infrastructure, loss or manipulation of password data can disrupt monitoring capabilities, leading to reduced visibility into system health and security posture. This can cause delayed detection of outages or security incidents, increasing organizational risk. Additionally, unauthorized removal of passwords may allow attackers to escalate privileges or disrupt automated processes dependent on these credentials. The vulnerability affects the integrity and availability of monitoring data but has limited direct impact on confidentiality since no direct data exfiltration is indicated. Organizations relying heavily on Checkmk for critical infrastructure monitoring, including enterprises, managed service providers, and data centers, may face operational disruptions and increased incident response costs. The medium severity rating suggests that while the threat is serious, it requires some level of access and does not allow full system compromise without additional vulnerabilities.

CWE-863Incorrect Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #17OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

checkmk.com/werk/19041 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Mar 2026, 14:02 UTC

WeaknessesCWE-863

Technical details

References

Community reviews

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