A 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 un…

published 2017-12-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2017-3124

cvss: 6.1; version 3.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.0%; EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits: 0; none known

A 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 unauthenticated attacker to inject arbitrary HTML or JavaScript via the output_format parameter, and the username parameter of failed HTTP basic authentication attempts, which is returned unencoded in an internal server error page.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2017-11507 updated 2026-05-13 cvss 6.1

check-mk: Stored XSS vulnerability using the internal server error handler

Red Hat Storage 3 check-mk, check-mk-livestatus
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.03% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

tenable.com https://www.tenable.com/security/research/tra-2017-20 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.0	6.1	CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:N/I:P/A:N

Affected products

Tenable Check_MK

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

tenable.com /security/research/tra-2017-20
exploit, third-party-advisory
mathias-kettner.com /check_mk_werks.php?werk_id=7661
vendor-advisory

Sources

CVE List CVE-2017-11507
NVD CVE-2017-11507

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary