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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2023-22421

24
FAUCET Score

CVE-2023-22421 is an out-of-bounds read vulnerability affecting Kostac PLC Programming Software (formerly Koyo PLC Programming Software) versions 1.6.9.0 and earlier. This flaw stems from insufficient buffer size for PLC program instructions, allowing a specially crafted project file to trigger the vulnerability. Rated 7.8 HIGH, successful exploitation requires user interaction (opening the malicious file) and can lead to information disclosure, arbitrary code execution, and full system compromise. There is currently no public exploit code or active exploitation observed, but it has garnered some community discussion and media coverage, including a CISA warning.

Impacted Technologies

VendorProductVersion(s)CPE
<= 1.6.9.0CPE matchmatch criteria
cpe:2.3:a:jtekt:kostac_plc_programming_software:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.8HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.32%
Probability of exploitation in next 30 days
EPSS Percentile
24.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0032 is in the 23rd percentile among its peer group of 11,621 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

jvn.jp / en/vu/JVNVU94966432
Third Party Advisory
electronics.jtekt.co.jp / en/topics/202303035258
Vendor Advisory
electronics.jtekt.co.jp / jp/topics/2023030313639
Vendor Advisory