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Checkmk CVE-2023-22288

MEDIUM
Improper Neutralization of Special Elements (CWE-138)
2023-03-20 security@checkmk.com
5.4
CVSS 3.1 · NVD
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Improper neutralization of special elements
Impact

CVSS score of 5.4 (MEDIUM). Attack characteristics: network attack vector, low complexity, low privileges required, user interaction required.

Exploit ScenarioDerived

This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAI

HTML Email Injection in Tribe29 Checkmk <=2.1.0p23; <=2.0.0p34, and all versions of Checkmk 1.6.0 allows an authenticated attacker to inject malicious HTML into Emails. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-138. HTML Email Injection in Tribe29 Checkmk <=2.1.0p23; <=2.0.0p34, and all versions of Checkmk 1.6.0 allows an authenticated attacker to inject malicious HTML into Emails Affected products include: Checkmk, Tribe29 Checkmk.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.4 MEDIUM
AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

DescriptionNVD

HTML Email Injection in Tribe29 Checkmk <=2.1.0p23; <=2.0.0p34, and all versions of Checkmk 1.6.0 allows an authenticated attacker to inject malicious HTML into Emails

Threat Intelligence Overview

EPSS Score
0.4%
Top 68% exploitable
Data Quality
2 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.4%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

27
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +27
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Code Injection CRITICAL

Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.

Affected Products (CPE)NVD

cpe:2.3:a:checkmk:checkmk:2.0.0:-:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:b1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:b2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:b3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:b4:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:b5:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:b6:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:b7:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:b8:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:i1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:p1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:p10:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:p11:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:p12:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:p13:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:p14:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:p15:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:p16:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:p17:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.0.0:p18:*:*:*:*:*:*
+ 57 more
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5.9 Oct 02

Check_MK before 1.2.8p26 mishandles certain errors within the failed-login save feature because of a race condition, whi

CVE-2021-40904 HIGH POC
8.8 Mar 25

The web management console of CheckMK Raw Edition (versions 1.5.0 to 1.6.0) allows a misconfiguration of the web-app Dok

CVE-2021-40905 HIGH POC
8.8 Mar 25

The web management console of CheckMK Enterprise Edition (versions 1.5.0 to 2.0.0p9) does not properly sanitise the uplo

CVE-2025-32919 HIGH POC
8.8 Oct 09

Local privilege escalation in the Checkmk Windows Agent's Windows License plugin allows an authenticated low-privileged

CVE-2025-39663 HIGH POC
8.5 Oct 30

Stored/transmitted cross-site scripting in Checkmk's distributed monitoring lets an attacker who already controls a remo

CVE-2025-39664 HIGH POC
7.1 Oct 09

Authenticated path traversal in Checkmk's report scheduler lets a user with valid application credentials write report f

CVE-2024-28825 CRITICAL
9.8 Apr 24

Improper restriction of excessive authentication attempts on some authentication methods in Checkmk before 2.3.0b5 (beta

CVE-2021-36563 MEDIUM POC
5.4 Jul 26

The CheckMK management web console (versions 1.5.0 to 2.0.0) does not sanitise user input in various parameters of the W

CVE-2025-39666 CRITICAL
9.3 Apr 07

Local privilege escalation in Checkmk allows site users with high privileges to escalate to root by manipulating site co

CVE-2024-8606 CRITICAL
9.2 Sep 23

Bypass of two factor authentication in RestAPI in Checkmk < 2.3.0p16 and < 2.2.0p34 allows authenticated users to bypass

CVE-2023-31209 HIGH
8.8 Aug 10

Improper neutralization of active check command arguments in Checkmk < 2.1.0p32, < 2.0.0p38, < 2.2.0p4 leads to arbitrar

CVE-2023-31208 HIGH
8.8 May 17

Improper neutralization of livestatus command delimiters in the RestAPI in Checkmk < 2.0.0p36, < 2.1.0p28, and < 2.2.0b8

References

Advisories & patches

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