CVE-2024-28833Network attack vector

Second-factor bypass via uncounted authentication failures

Published Jun 10, 2024 · Updated Aug 2, 2024

Improper authentication-attempt restriction in Checkmk 2.3 before 2.3.0p6 allows remote attackers to bypass two-factor protection. Two-factor failures were omitted from the failed-login counter, so repeated incorrect second factors never triggered the account lockout applied to other login failures. The attack requires reaching a two-factor challenge for a user account and can expose data protected by that account.

CVSS severity5.9
Medium
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication-attempt restriction in Checkmk 2.3 before 2.3.0p6 allows remote attackers to bypass two-factor protection. Two-factor failures were omitted from the failed-login counter, so repeated incorrect second factors never triggered the account lockout applied to other login failures. The attack requires reaching a two-factor challenge for a user account and can expose data protected by that account.

The record

CVE
CVE-2024-28833
Published
Jun 10, 2024
Updated
Aug 2, 2024
Vendor
Checkmk GmbH
Product
Checkmk
Classifications
CWE-307, T1110
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 10, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record 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.

  1. Affected versionversion=2.3.0 <2.3.0p6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Checkmk GmbH · Checkmkversion=2.3.0 <2.3.0p6

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.9Checkmk GmbHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-307Improper Restriction of Excessive Authentication Attempts
T1110Brute Force

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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