Authenticated host enumeration via permission-check ordering
Published Mar 13, 2026 · Updated Mar 13, 2026
Observable response discrepancy in Checkmk 2.4.0, 2.3.0, and 2.2.0 releases allows remote authenticated users to enumerate hosts. The agent-receiver/register_existing endpoint checks whether a requested host exists before it verifies the user's permission, exposing 404 for absent hosts and 403 for existing but forbidden hosts. Any authenticated account can exploit the discrepancy in the default configuration, disclosing monitored host names without granting access to their data.
Summary
What happened
Observable response discrepancy in Checkmk 2.4.0, 2.3.0, and 2.2.0 releases allows remote authenticated users to enumerate hosts. The agent-receiver/register_existing endpoint checks whether a requested host exists before it verifies the user's permission, exposing 404 for absent hosts and 403 for existing but forbidden hosts. Any authenticated account can exploit the discrepancy in the default configuration, disclosing monitored host names without granting access to their data.
The record
- CVE
- CVE-2026-24097
- Published
- Mar 13, 2026
- Updated
- Mar 13, 2026
- Vendor
- Checkmk GmbH
- Product
- Checkmk
- Classifications
- CWE-204, CAPEC-180, T1018
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 13, 2026CVE publishedPublication date reported by the CVE source.
- Mar 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.2.0
- Affected versionversion=2.3.0 <2.3.0p43
- Affected versionversion=2.4.0 <2.4.0p23
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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