VULNERABILITY INTELLIGENCE

CVE-2021-21958

CVSS score7.8 HIGH

EPSS probability1.10%

CISA KEVNot currently listed

Published2022-02-16

Last modified2026-06-17

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

Description

A heap-based buffer overflow vulnerability exists in the Hword HwordApp.dll functionality of Hancom Office 2020 11.0.0.2353. A specially-crafted malformed file can lead to memory corruption and potential arbitrary code execution. An attacker can provide a malicious file to trigger this vulnerability.

Weakness classification

CWE-122: Heap-based Buffer Overflow
CWE-787: Out-of-bounds Write

Primary references

talos-cna@cisco.com — Exploit, Third Party Advisory
nvd@nist.gov — Exploit, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108 — Exploit, Third Party Advisory