CVE-2021-20836

Out-of-bounds read vulnerability in CX-Supervisor v4.0.0.13 and v4.0.0.16 allows an attacker with administrative privileges to cause information disclosure and/or arbitrary code execution by opening a specially crafted SCS project files.

Published: 2021-10-18 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-20836 is rated Moderate Risk (43.7/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.78%). Review affected assets and schedule remediation.

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-2021-20836

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 0.90% 0.78% -0.12%
2 2025-03-30 0.74% 0.90% +0.16%
3 2025-03-29 — 0.74% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-20836

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:H)
They need powerful rights—admin, root, or similar—before this pays off.
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.
 0.6 5.9 [email protected]
6.0 2.0 MEDIUM
AV:N/AC:M/Au:S/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:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 6.8 6.4 [email protected]

Weakness enumeration for CVE-2021-20836

Affected software / configurations for CVE-2021-20836

Vendor Product Version Raw CPE
omron cx-supervisor 4.0.0.13 cpe:2.3:a:omron:cx-supervisor:4.0.0.13:*:*:*:*:*:*:*
omron cx-supervisor 4.0.0.16 cpe:2.3:a:omron:cx-supervisor:4.0.0.16:*:*:*:*:*:*:*

References for CVE-2021-20836

URL Tags
https://jvn.jp/en/vu/JVNVU90041391/index.html Release Notes Third Party Advisory
https://www.myomron.com/index.php?action=kb&article=1692 Patch Vendor Advisory
cvelogic Threat Intelligence