CVE-2023-31211Network attack vector

Authentication bypass via omitted disabled-user check

Published Jan 12, 2024 · Updated Jun 17, 2025

Authentication bypass in Checkmk before 2.2.0p18, 2.1.0p38, and 2.0.0p39 allows remote authenticated users to retain account access. The automation-user authentication path accepts the supplied credentials but omits the account-disabled check before granting access. Exploitation requires valid credentials for a disabled automation user and grants the permissions already assigned to that account.

CVSS severity8.8
High
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Checkmk before 2.2.0p18, 2.1.0p38, and 2.0.0p39 allows remote authenticated users to retain account access. The automation-user authentication path accepts the supplied credentials but omits the account-disabled check before granting access. Exploitation requires valid credentials for a disabled automation user and grants the permissions already assigned to that account.

The record

CVE
CVE-2023-31211
Published
Jan 12, 2024
Updated
Jun 17, 2025
Vendor
Checkmk GmbH
Product
Checkmk
Classifications
CWE-303, T1078
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 12, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 2025Record 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=2.0.0 <=2.0.0p39
  2. Affected versionversion=2.1.0 <2.1.0p38
  3. Affected versionversion=2.2.0 <2.2.0p18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Checkmk GmbH · Checkmkversion=2.0.0 <=2.0.0p39; version=2.1.0 <2.1.0p38; version=2.2.0 <2.2.0p18

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
8.8Checkmk GmbHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-303Incorrect Implementation of Authentication Algorithm
T1078Valid Accounts

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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