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Vulnerability record · CVE-2017-9781 · published 21 June 2017

CVE-2017-9781: Check mk project check mk cross-site scripting vulnerability

Check Mk Project · Check Mk

A cross site scripting (XSS) vulnerability exists in Check_MK versions 1.4.0x prior to 1.4.0p6, allowing an unauthenticated remote attacker to inject arbitrary HTML or JavaScript via the _username parameter when attempting authentication to webapi.py, which is returned unencoded with content type text/html.

6.1 CVSS 3.0 Medium EPSS 1.6% · top 25.8% CWE-79 · Cross-site scripting
6.1CVSS 3.0 base score, v2 4.3
1.6%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

A cross site scripting (XSS) vulnerability exists in Check_MK versions 1.4.0x prior to 1.4.0p6, allowing an unauthenticated remote attacker to inject arbitrary HTML or JavaScript via the _username parameter when attempting authentication to webapi.py, which is returned unencoded with content type text/html.

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://git.mathias-kettner.de/git/?p=check_mk.git%3Ba=blob%3Bf=.werks/4757%3Bhb=c248f0b6ff7b15ced9f07a3df8a80fad656ea5b1
https://www.tenable.com/security/research/tra-2017-21 ExploitThird Party Advisory
http://git.mathias-kettner.de/git/?p=check_mk.git%3Ba=blob%3Bf=.werks/4757%3Bhb=c248f0b6ff7b15ced9f07a3df8a80fad656ea5b1
https://www.tenable.com/security/research/tra-2017-21 ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.3CVE-2014-5340Check mk project check mk code injection vulnerabilityThe wato component in Check_MK before 1.2.4p4 and 1.2.5 before 1.2.5i4 uses the pickle Python module unsafely, which allows remote attackers to execu…EPSS 6.1%8.5CVE-2014-2331Check mk project check mk code injection vulnerabilityCheck_MK 1.2.2p2, 1.2.2p3, and 1.2.3i5 allows remote authenticated users to execute arbitrary Python code via a crafted rules.mk file in a snapshot. …EPSS 2.1%6.8CVE-2014-2330Check mk project check mk cross-site request forgery vulnerabilityMultiple cross-site request forgery (CSRF) vulnerabilities in the Multisite GUI in Check_MK before 1.2.5i2 allow remote attackers to hijack the authe…EPSS 1.1%6.1CVE-2017-11507Check mk project check mk cross-site scripting vulnerabilityA cross site scripting (XSS) vulnerability exists in Check_MK versions 1.2.8x prior to 1.2.8p25 and 1.4.0x prior to 1.4.0p9, allowing an unauthentica…EPSS 1.0%5.5CVE-2014-0243Check mk project check mk link following vulnerabilityCheck_MK through 1.2.5i2p1 allows local users to read arbitrary files via a symlink attack to a file in /var/lib/check_mk_agent/job.EPSS 0.59%5.5CVE-2014-2332Check mk project check mk improper input validation vulnerabilityCheck_MK before 1.2.2p3 and 1.2.3x before 1.2.3i5 allows remote authenticated users to delete arbitrary files via a request to an unspecified link, r…EPSS 1.4%4.9CVE-2014-5339Check mk project check mk vulnerabilityCheck_MK before 1.2.4p4 and 1.2.5 before 1.2.5i4 allows remote authenticated users to write check_mk config files (.mk files) to arbitrary locations …EPSS 1.8%3.5CVE-2014-2329Check mk project check mk cross-site scripting vulnerabilityMultiple cross-site scripting (XSS) vulnerabilities in Check_MK before 1.2.2p3 and 1.2.3x before 1.2.3i5 allow remote authenticated users to inject a…EPSS 1.1%

Source: NIST National Vulnerability Database (record CVE-2017-9781), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.