What is CVE-2021-40906?

CVE-2021-40906 is a medium-severity vulnerability in Checkmk, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2022-03-25.

How severe is CVE-2021-40906?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Is CVE-2021-40906 known to be exploited?

9 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

XSS in Checkmk

CVE-2021-40906

CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web service parameter that is in an unauthenticated zone. This Reflected XSS allows an attacker to open a backdoor on the device with HTML content and interpreted by the browser (such as JavaScript or other client-side scripts) or to steal the session cookies of a user who has previously authenticated via a man in the middle. Successful exploitation requires access to the web service resource without authentication.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.010 (60.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Checkmk — versions 1.6.0
Tribe29 Checkmk — versions 1.6.0b10, 1.6.0b11, 1.6.0p10
N/a — versions n/a

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

References

af854a3a-2127-422b-91ae-364da2661108 (Product, x_refsource_MISC)
cve@mitre.org (Third Party Advisory, x_refsource_MISC)

Frequently asked questions

What is CVE-2021-40906?: CVE-2021-40906 is a medium-severity vulnerability in Checkmk, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2022-03-25.
How severe is CVE-2021-40906?: Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2021-40906 known to be exploited?: 9 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.