CVE-2021-32198Network attack vector

GUI hang via unthrottled title updates

Published Jun 6, 2021 · Updated Aug 3, 2024

Denial of service in EmTec ZOC through 8.02.4 allows remote attackers controlling a connected server to hang the Windows GUI. ZOC processes rapid remote window-title escape sequences without throttling, repeatedly invoking SetWindowTextA or SetWindowTextW until the interface becomes unresponsive. Exploitation requires an active terminal session to an attacker-controlled server; the documented consequence is a GUI hang, not data access or code execution.

CVSS severity9.8
Critical
EPSS probability1.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in EmTec ZOC through 8.02.4 allows remote attackers controlling a connected server to hang the Windows GUI. ZOC processes rapid remote window-title escape sequences without throttling, repeatedly invoking SetWindowTextA or SetWindowTextW until the interface becomes unresponsive. Exploitation requires an active terminal session to an attacker-controlled server; the documented consequence is a GUI hang, not data access or code execution.

The record

CVE
CVE-2021-32198
Published
Jun 6, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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