Check_MK before 1.2.8p26 mishandles certain errors within the failed-login save feature because of a race condition, which allows remote at…

published 2017-10-01 9 y ago modified 2026-06-17 4 mo ago also EUVD-2017-6431

cvss: 5.9; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 12.1%; EPSS 12.1% chance of exploitation in 30 days, percentile 96%
public exploits: 1; Exploit-DB

Check_MK before 1.2.8p26 mishandles certain errors within the failed-login save feature because of a race condition, which allows remote attackers to obtain sensitive user information by reading a GUI crash report.

Patch / fix

distros 1

check-mk Ubuntu 18.04 LTS 1.2.8p16-1ubuntu0.2
check-mk Ubuntu Pro 16.04 LTS 1.2.6p12-1ubuntu0.16.04.1+esm1

ubuntu advisories UBUNTU-CVE-2017-14955

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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-2017-14955 updated 2026-05-13 cvss 6.5

check-mk: Mishandles certain errors within the failed-login save feature because of a race condition

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

Timeline

2017-10-01 Published
2017-10-18 First public exploit (EDB-43021)

Exploit prediction

12.13% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

EDB-43021 Check_MK 1.2.8p25 - Information Disclosure webapps, 2017-10-18

CVSS scores

assigned by	version	score	vector
NVD	3.1	5.9	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:P/I:N/A:N

Classification

Weakness

CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

References

exploit-db.com /exploits/43021/
exploit, third-party-advisory, vdb-entry
mathias-kettner.com /check_mk_werks.php?edition_id=raw&branch=1.2.8
release-notes, third-party-advisory
mathias-kettner.de /check_mk_werks.php?werk_id=5208&HTML=yes
third-party-advisory

Sources

CVE List CVE-2017-14955
NVD CVE-2017-14955

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