CVE-2026-15576 | BDVDB-2026-363296 Detail

CheckmkCheckmk

Description#

Improper authentication in the agent receiver of Checkmk <2.5.0p10 allows an unauthenticated remote attacker to bypass mutual TLS client certificate verification of relay endpoints by supplying a fixed placeholder identity in the request URL, resulting in limited impact on integrity and availability. Only the Cloud, Ultimate and Ultimate MT editions are affected, as other editions do not expose relay endpoints.

Impact#

CAPEC-115: Authentication Bypass

Weaknesses#

CWE-306 Missing Authentication for Critical Function

References#

https://checkmk.com/werk/20174

Exploit#

No public exploit known

History#

Version 12026-08-21Record published in the CVE List.

Published

Published: 2026-08-21
Last modified: 2026-08-21

Vendor information

Vendor: Checkmk
Product: Checkmk

All Checkmk vulnerabilities

Score

6.9 Medium

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 39.6.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Authentication Issues

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
>= 2.5.0 and < 2.5.0p10
Fixed
2.5.0p10

Scoring System

CVSS v4.0

6.9 Medium

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Attack Requirements	None
Privileges Required	None
User Interaction	None
Vulnerable System Confidentiality	None
Vulnerable System Integrity	Low
Vulnerable System Availability	Low
Subsequent System Confidentiality	None
Subsequent System Integrity	None
Subsequent System Availability	None

CVSS v3.1

Not available

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).