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CVE-2026-24097

Authenticated Host Enumeration via Observable Response Discrepancy on Agent Register Existing Endpoint

5.3 Medium

Improper permission enforcement in Checkmk versions 2.4.0 before 2.4.0p23, 2.3.0 before 2.3.0p43, and 2.2.0 (EOL) allows authenticated users to enumerate existing hosts by observing different HTTP response codes in agent-receiver/register_existing endpoint, which could lead to information disclosure.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
None
Availability
None

Exploit likelihood

0.25%Up 0.2 points since Mar 13, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.3

Authenticated Host Enumeration via Observable Response Discrepancy on Agent Register Existing Endpoint

Improper permission enforcement in Checkmk versions 2.4.0 before 2.4.0p23, 2.3.0 before 2.3.0p43, and 2.2.0 (EOL) allows authenticated users to enumerate existing hosts by observing different HTTP response codes in agent-receiver/register_existing endpoint, which could lead to information disclosure.

Record
CVE-2026-24097
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Weakness
CWE-204
Updated
2026-11-02
EUVDEUVD-2026-11782 5.3

Improper permission enforcement in Checkmk versions 2.4.0 before 2.4.0p23, 2.3.0 before 2.3.0p43, and 2.2.0 (EOL) allows authenticated users to enumerate existing hosts by observing different HTTP response codes in agent-receiver/register_existing endpoint, which could lead to information disclosure.

Record
EUVD-2026-11782
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-34x2-m38g-824f 5.3

Improper permission enforcement in Checkmk versions 2.4.0 before 2.4.0p23, 2.3.0 before 2.3.0p43,...

Improper permission enforcement in Checkmk versions 2.4.0 before 2.4.0p23, 2.3.0 before 2.3.0p43, and 2.2.0 (EOL) allows authenticated users to enumerate existing hosts by observing different HTTP response codes in agent-receiver/register_existing endpoint, which could lead to information disclosure.

Record
GHSA-34x2-m38g-824f
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weakness
CWE-204
Updated
2026-11-02
NVD 5.3

Improper permission enforcement in Checkmk versions 2.4.0 before 2.4.0p23, 2.3.0 before 2.3.0p43, and 2.2.0 (EOL) allows authenticated users to enumerate existing hosts by observing different HTTP response codes in agent-receiver/register_existing endpoint, which could lead to information disclosure.

Record
CVE-2026-24097
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weakness
CWE-204
Updated
2026-11-02
OSV 5.3

Authenticated Host Enumeration via Observable Response Discrepancy on Agent Register Existing Endpoint

Improper permission enforcement in Checkmk versions 2.4.0 before 2.4.0p23, 2.3.0 before 2.3.0p43, and 2.2.0 (EOL) allows authenticated users to enumerate existing hosts by observing different HTTP response codes in agent-receiver/register_existing endpoint, which could lead to information disclosure.

Record
CVE-2026-24097
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Weakness
CWE-204
Updated
2026-11-02
OSVUBUNTU-CVE-2026-24097 5.3

Improper permission enforcement in Checkmk versions 2.4.0 before 2.4.0p23, 2.3.0 before 2.3.0p43, and 2.2.0 (EOL) allows authenticated users to enumerate existing hosts by observing different HTTP response codes in agent-receiver/register_existing endpoint, which could lead to information disclosure.

Record
UBUNTU-CVE-2026-24097
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
CVSS 3.1
4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
check-mk
Ubuntu:Pro:16.04:LTS
All versions, plus listed versions
1.2.6p5-11.2.6p12-11.2.6p12-1ubuntu0.16.04.11.2.6p12-1ubuntu0.16.04.1+esm1
None known
check-mk
Ubuntu:18.04:LTS
All versions, plus listed versions
1.2.8p16-1ubuntu0.11.2.8p16-1ubuntu0.2
None known

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-24097 is a medium vulnerability (CVSS 5.3) in Checkmk, published March 13, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.25%, the 16th percentile. No source names a fixed version.

References

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