CVE-2023-2020 | Unauthorized scheduling of downtimes via REST API

Insufficient permission checks in the REST API in Tribe29 Checkmk <= 2.1.0p27 and <= 2.2.0b4 (beta) allow unauthorized users to schedule downtimes for any host.

Published: 2023-04-18 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-2020 is rated Low Risk (28.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.40%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-2020

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.17% 0.40% +0.24%
2 2026-04-19 0.10% 0.17% +0.06%
3 2025-03-30 — 0.10% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-2020

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]
4.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]

Weakness enumeration for CVE-2023-2020

OS Trackers for CVE-2023-2020

vendor priority summary link
ubuntu medium CVE-2023-2020 medium priority: Ubuntu including 1 source packages (check-mk), 13 status rows across 13 suites (bionic, focal, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 9, needs-triage 3, ignored 1. https://ubuntu.com/security/CVE-2023-2020

Affected software / configurations for CVE-2023-2020

Vendor Product Version Raw CPE
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:-:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:b1:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:b2:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:b3:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:b4:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:b5:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:b6:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:b7:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:b8:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:b9:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p1:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p10:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p11:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p12:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p13:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p14:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p15:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p16:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p17:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p18:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p2:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p20:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p21:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p22:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p23:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p24:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p25:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p26:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p27:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p3:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p4:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p5:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p6:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p7:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p8:*:*:*:*:*:*
checkmk checkmk 2.1.0 cpe:2.3:a:checkmk:checkmk:2.1.0:p9:*:*:*:*:*:*
checkmk checkmk 2.2.0 cpe:2.3:a:checkmk:checkmk:2.2.0:b1:*:*:*:*:*:*
checkmk checkmk 2.2.0 cpe:2.3:a:checkmk:checkmk:2.2.0:b2:*:*:*:*:*:*
checkmk checkmk 2.2.0 cpe:2.3:a:checkmk:checkmk:2.2.0:b3:*:*:*:*:*:*
checkmk checkmk 2.2.0 cpe:2.3:a:checkmk:checkmk:2.2.0:b4:*:*:*:*:*:*
checkmk checkmk 2.2.0 cpe:2.3:a:checkmk:checkmk:2.2.0:i1:*:*:*:*:*:*

References for CVE-2023-2020

URL Tags
https://checkmk.com/werk/13981 Vendor Advisory
cvelogic Threat Intelligence