CVE-2021-40905

Exp

The web management console of CheckMK Enterprise Edition (versions 1.5.0 to 2.0.0p9) does not properly sanitise the uploading of ".mkp" files, which are Extension Packages, making remote code execution possible. Successful exploitation requires access to the web management interface, either with valid credentials or with a hijacked session of a user with administrator role. NOTE: the vendor states that this is the intended behavior: admins are supposed to be able to execute code in this manner

Published: 2022-03-25 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-40905 is rated High Exploit Risk (77.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.81%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2021-40905

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-40905

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 4.88% 2.81% -2.07%
2 2025-12-10 3.01% 4.88% +1.87%
3 2025-11-21 — 3.01% —

Full EPSS history (31 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-40905

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H 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:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H 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:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2021-40905

Affected software / configurations for CVE-2021-40905

Vendor Product Version Raw CPE
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:-:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:b1:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:b2:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:b3:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:b4:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:b5:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:b6:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:b7:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:b8:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:i1:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p1:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p10:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p11:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p12:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p13:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p14:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p15:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p16:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p17:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p2:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p3:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p4:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p5:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p6:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p7:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p8:*:*:*:*:*:*
checkmk checkmk 2.0.0 cpe:2.3:a:checkmk:checkmk:2.0.0:p9:*:*:*:*:*:*
tribe29 checkmk >= 1.5.0, < 2.0.0 cpe:2.3:a:tribe29:checkmk:*:*:*:*:*:*:*:*

References for CVE-2021-40905

URL Tags
http://checkmk.com Product
https://github.com/Edgarloyola/CVE-2021-40905 Exploit Third Party Advisory
cvelogic Threat Intelligence