CVE-2021-26608: handysoft groupware arbitrary file download and execution vulnerability

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-09-09 · updated 2026-06-17
Weakness: CWE-353

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.

Affected products

handysoft HShell.dll: 1.7.4.5, 2.0.3.5, 4.0.1.6

References

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

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