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.
References
History

Tue, 09 Jun 2026 15:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:checkmk:checkmk:2.2.0:-:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:b1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:b2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:b3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:b4:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:b5:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:b6:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:b7:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:b8:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:i1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p10:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p11:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p12:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p13:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p14:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p15:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p16:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p17:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p18:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p19:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p20:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p21:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p22:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p23:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p24:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p25:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p26:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p27:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p28:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p29:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p30:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p31:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p32:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p33:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p34:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p35:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p36:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p37:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p38:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p39:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p40:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p41:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p42:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p43:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p44:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p45:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p46:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p47:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p4:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p5:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p6:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p7:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p8:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:p9:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:-:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:b1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:b2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:b3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:b4:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:b5:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:b6:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p10:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p11:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p12:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p13:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p14:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p15:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p16:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p17:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p18:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p19:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p20:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p21:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p22:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p23:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p24:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p25:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p26:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p27:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p28:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p29:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p30:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p31:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p32:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p33:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p34:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p35:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p36:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p37:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p38:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p39:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p40:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p41:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p42:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p43:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p44:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p45:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p46:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p47:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p4:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p5:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p6:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p7:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p8:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p9:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:*:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:-:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:b1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:b2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:b3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:b4:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:b5:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:b6:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p10:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p11:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p12:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p13:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p14:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p15:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p16:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p17:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p18:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p19:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p20:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p21:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p22:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p23:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p24:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p25:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p26:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p27:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p28:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p29:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p30:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p4:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p5:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p6:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p7:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p8:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p9:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.5.0:-:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.5.0:b1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.5.0:b2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.5.0:b3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.5.0:p1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.5.0:p2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.5.0:p3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.5.0:p4:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N'}


Mon, 08 Jun 2026 13:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Mon, 08 Jun 2026 13:00:00 +0000

Type Values Removed Values Added
Description 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.
Title XSS in urls
First Time appeared Checkmk
Checkmk checkmk
Weaknesses CWE-79
CPEs cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.2.0:*:*:*:*:*:*:*
Vendors & Products Checkmk
Checkmk checkmk
References
Metrics cvssV4_0

{'score': 8.5, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:L/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: Checkmk

Published: 2026-06-08T12:06:51.267Z

Updated: 2026-06-08T13:02:45.679Z

Reserved: 2026-05-18T14:06:43.958Z

Link: CVE-2026-8833

cve-icon Vulnrichment

Updated: 2026-06-08T13:02:42.423Z

cve-icon NVD

Status : Analyzed

Published: 2026-06-08T13:16:33.900

Modified: 2026-06-09T14:49:31.967

Link: CVE-2026-8833

cve-icon Redhat

No data.