CVE-2022-33896: A buffer underflow vulnerability exists in the way Hword of Hancom Office 2020 version 11.0.0.5357 parses XML-based o…

Is it exploited?

Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of 29 Oct 2026.

VulnCheck KEV lists it since 27 Oct 2025. It cites 1 public report, the first from 27 Oct 2025.

• 38north.org

How likely is exploitation in the next 30 days?

0.5%

EPSS score, percentile 44.7 of all scored records. A probability estimated by FIRST, not a report of exploitation.

CISA's SSVC assessment in the CVE record lists exploitation as poc.

How severe?

7.8 High

CVSS v3.0 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

• Hancom Office 2020 11.0.0.5357

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; VulnCheck KEV, as of 30 Oct 2026; FIRST EPSS, as of 30 Oct 2026; CVE List, as of 30 Oct 2026. About the data.

Description

A buffer underflow vulnerability exists in the way Hword of Hancom Office 2020 version 11.0.0.5357 parses XML-based office files. A specially-crafted malformed file can cause memory corruption by using memory before buffer start, which can lead to code execution. A victim would need to access a malicious file to trigger this vulnerability.

Source: CVE List, as of 30 Oct 2026. About the data.

What to do

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

This summary is based on the CVE record as of 30 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

Source: CVE List, as of 30 Oct 2026. About the data.

Timeline