CVE-2021-26608

Name: CVE-2021-26608
Creator: NVD / NIST
Published: 2021-09-09T13:15:08.543+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 0.58%

Last modified Jun 17, 2026

CVE-2021-26608 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. An arbitrary file download and execution vulnerability was found in the HShell.dll of handysoft Co., Ltd groupware ActiveX module. This issue is due to missing support for integrity check of download URL or downloaded file hash.. EPSS estimates a 0.58% chance of exploitation in the next 30 days.

Description

An arbitrary file download and execution vulnerability was found in the HShell.dll of handysoft Co., Ltd groupware ActiveX module. This issue is due to missing support for integrity check of download URL or downloaded file hash.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

0.58%

43.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Handysoft	Hshell	1.7.4.5
Handysoft	Hshell	2.0.3.5
Handysoft	Hshell	4.0.1.6

References

https://www.boho.or.kr/krcert/secNoticeView.do?bulletin_writing_sequence=36239Third Party Advisory
https://www.boho.or.kr/krcert/secNoticeView.do?bulletin_writing_sequence=36239Third Party Advisory

Timeline

Published: Sep 9, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-26608?

How severe is CVE-2021-26608?

CVE-2021-26608 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.58% probability of exploitation in the next 30 days.

How do I fix CVE-2021-26608?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-26608?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST