CVE-2026-8833: XSS in urls

Published Jun 8, 2026
·
Updated

Improper neutralization of HTML-encoded characters in the URL validation function in Checkmk <2.5.0p5, <2.4.0p31, <2.3.0p48, and all 2.2.0 versions allows an authenticated user to bypass URL validation and inject malicious URLs such as javascript: URIs, resulting in cross-site scripting when another user interacts with the crafted link.

Affected Software

158 affected components
Checkmk Checkmk<2.5.0p5, <2.4.0p31, <2.3.0p48, >=2.2.0<=2.2.0
Checkmk Checkmk=2.2.0
Checkmk Checkmk=2.2.0-b1
Checkmk Checkmk=2.2.0-b2
Checkmk Checkmk=2.2.0-b3
Checkmk Checkmk=2.2.0-b4
Checkmk Checkmk=2.2.0-b5
Checkmk Checkmk=2.2.0-b6
Checkmk Checkmk=2.2.0-b7
Checkmk Checkmk=2.2.0-b8
Checkmk Checkmk=2.2.0-i1
Checkmk Checkmk=2.2.0-p1
Checkmk Checkmk=2.2.0-p10
Checkmk Checkmk=2.2.0-p11
Checkmk Checkmk=2.2.0-p12
Checkmk Checkmk=2.2.0-p13
Checkmk Checkmk=2.2.0-p14
Checkmk Checkmk=2.2.0-p15
Checkmk Checkmk=2.2.0-p16
Checkmk Checkmk=2.2.0-p17
Checkmk Checkmk=2.2.0-p18
Checkmk Checkmk=2.2.0-p19
Checkmk Checkmk=2.2.0-p2
Checkmk Checkmk=2.2.0-p20
Checkmk Checkmk=2.2.0-p21
Checkmk Checkmk=2.2.0-p22
Checkmk Checkmk=2.2.0-p23
Checkmk Checkmk=2.2.0-p24
Checkmk Checkmk=2.2.0-p25
Checkmk Checkmk=2.2.0-p26
Checkmk Checkmk=2.2.0-p27
Checkmk Checkmk=2.2.0-p28
Checkmk Checkmk=2.2.0-p29
Checkmk Checkmk=2.2.0-p3
Checkmk Checkmk=2.2.0-p30
Checkmk Checkmk=2.2.0-p31
Checkmk Checkmk=2.2.0-p32
Checkmk Checkmk=2.2.0-p33
Checkmk Checkmk=2.2.0-p34
Checkmk Checkmk=2.2.0-p35
Checkmk Checkmk=2.2.0-p36
Checkmk Checkmk=2.2.0-p37
Checkmk Checkmk=2.2.0-p38
Checkmk Checkmk=2.2.0-p39
Checkmk Checkmk=2.2.0-p4
Checkmk Checkmk=2.2.0-p40
Checkmk Checkmk=2.2.0-p41
Checkmk Checkmk=2.2.0-p42
Checkmk Checkmk=2.2.0-p43
Checkmk Checkmk=2.2.0-p44
Checkmk Checkmk=2.2.0-p45
Checkmk Checkmk=2.2.0-p46
Checkmk Checkmk=2.2.0-p47
Checkmk Checkmk=2.2.0-p5
Checkmk Checkmk=2.2.0-p6
Checkmk Checkmk=2.2.0-p7
Checkmk Checkmk=2.2.0-p8
Checkmk Checkmk=2.2.0-p9
Checkmk Checkmk=2.3.0
Checkmk Checkmk=2.3.0-b1
Checkmk Checkmk=2.3.0-b2
Checkmk Checkmk=2.3.0-b3
Checkmk Checkmk=2.3.0-b4
Checkmk Checkmk=2.3.0-b5
Checkmk Checkmk=2.3.0-b6
Checkmk Checkmk=2.3.0-p1
Checkmk Checkmk=2.3.0-p10
Checkmk Checkmk=2.3.0-p11
Checkmk Checkmk=2.3.0-p12
Checkmk Checkmk=2.3.0-p13
Checkmk Checkmk=2.3.0-p14
Checkmk Checkmk=2.3.0-p15
Checkmk Checkmk=2.3.0-p16
Checkmk Checkmk=2.3.0-p17
Checkmk Checkmk=2.3.0-p18
Checkmk Checkmk=2.3.0-p19
Checkmk Checkmk=2.3.0-p2
Checkmk Checkmk=2.3.0-p20
Checkmk Checkmk=2.3.0-p21
Checkmk Checkmk=2.3.0-p22
Checkmk Checkmk=2.3.0-p23
Checkmk Checkmk=2.3.0-p24
Checkmk Checkmk=2.3.0-p25
Checkmk Checkmk=2.3.0-p26
Checkmk Checkmk=2.3.0-p27
Checkmk Checkmk=2.3.0-p28
Checkmk Checkmk=2.3.0-p29
Checkmk Checkmk=2.3.0-p3
Checkmk Checkmk=2.3.0-p30
Checkmk Checkmk=2.3.0-p31
Checkmk Checkmk=2.3.0-p32
Checkmk Checkmk=2.3.0-p33
Checkmk Checkmk=2.3.0-p34
Checkmk Checkmk=2.3.0-p35
Checkmk Checkmk=2.3.0-p36
Checkmk Checkmk=2.3.0-p37
Checkmk Checkmk=2.3.0-p38
Checkmk Checkmk=2.3.0-p39
Checkmk Checkmk=2.3.0-p4
Checkmk Checkmk=2.3.0-p40
Checkmk Checkmk=2.3.0-p41
Checkmk Checkmk=2.3.0-p42
Checkmk Checkmk=2.3.0-p43
Checkmk Checkmk=2.3.0-p44
Checkmk Checkmk=2.3.0-p45
Checkmk Checkmk=2.3.0-p46
Checkmk Checkmk=2.3.0-p47
Checkmk Checkmk=2.3.0-p5
Checkmk Checkmk=2.3.0-p6
Checkmk Checkmk=2.3.0-p7
Checkmk Checkmk=2.3.0-p8
Checkmk Checkmk=2.3.0-p9
Checkmk Checkmk=2.4.0
Checkmk Checkmk=2.4.0
Checkmk Checkmk=2.4.0-b1
Checkmk Checkmk=2.4.0-b2
Checkmk Checkmk=2.4.0-b3
Checkmk Checkmk=2.4.0-b4
Checkmk Checkmk=2.4.0-b5
Checkmk Checkmk=2.4.0-b6
Checkmk Checkmk=2.4.0-p1
Checkmk Checkmk=2.4.0-p10
Checkmk Checkmk=2.4.0-p11
Checkmk Checkmk=2.4.0-p12
Checkmk Checkmk=2.4.0-p13
Checkmk Checkmk=2.4.0-p14
Checkmk Checkmk=2.4.0-p15
Checkmk Checkmk=2.4.0-p16
Checkmk Checkmk=2.4.0-p17
Checkmk Checkmk=2.4.0-p18
Checkmk Checkmk=2.4.0-p19
Checkmk Checkmk=2.4.0-p2
Checkmk Checkmk=2.4.0-p20
Checkmk Checkmk=2.4.0-p21
Checkmk Checkmk=2.4.0-p22
Checkmk Checkmk=2.4.0-p23
Checkmk Checkmk=2.4.0-p24
Checkmk Checkmk=2.4.0-p25
Checkmk Checkmk=2.4.0-p26
Checkmk Checkmk=2.4.0-p27
Checkmk Checkmk=2.4.0-p28
Checkmk Checkmk=2.4.0-p29
Checkmk Checkmk=2.4.0-p3
Checkmk Checkmk=2.4.0-p30
Checkmk Checkmk=2.4.0-p4
Checkmk Checkmk=2.4.0-p5
Checkmk Checkmk=2.4.0-p6
Checkmk Checkmk=2.4.0-p7
Checkmk Checkmk=2.4.0-p8
Checkmk Checkmk=2.4.0-p9
Checkmk Checkmk=2.5.0
Checkmk Checkmk=2.5.0-b1
Checkmk Checkmk=2.5.0-b2
Checkmk Checkmk=2.5.0-b3
Checkmk Checkmk=2.5.0-p1
Checkmk Checkmk=2.5.0-p2
Checkmk Checkmk=2.5.0-p3
Checkmk Checkmk=2.5.0-p4

Event History

Jun 8, 2026
CVE Published
via MITRE·12:06 PM
Data Sourced
via MITRE·12:06 PM
DescriptionWeakness
Data Sourced
via NVD·01:16 PM
DescriptionSeverityWeaknessAffected Software
Jun 29, 58424
Event
via FIRST·12:52 PM

Frequently Asked Questions

1

What is the severity of CVE-2026-8833?

The severity of CVE-2026-8833 is rated as high with a score of 8.5.

2

How do I fix CVE-2026-8833?

To fix CVE-2026-8833, upgrade to Checkmk versions 2.5.0p5, 2.4.0p31, or 2.3.0p48 or later.

3

What kind of vulnerability is CVE-2026-8833?

CVE-2026-8833 is a cross-site scripting (XSS) vulnerability.

4

Who is affected by CVE-2026-8833?

Authenticated users of Checkmk versions older than 2.5.0p5, 2.4.0p31, and 2.3.0p48 are affected by CVE-2026-8833.

5

What is the potential impact of CVE-2026-8833?

The potential impact of CVE-2026-8833 allows an attacker to inject malicious URLs, resulting in cross-site scripting when other users interact with them.

Company

Resources

Contact

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info@secalerts.co
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