CVE-2021-23139

CGI crash via null pointer dereference

Published Oct 21, 2021 · Updated Aug 3, 2024

Null pointer dereference in Trend Micro Apex One 2019 and Worry-Free Business Security 10.0 SP1 allows attackers to crash the CGI program via crafted requests. The affected CGI handler dereferences a null pointer when processing attacker-controlled input, but public advisories do not identify the exact function or parameter. The vendor rates exploitation as adjacent-network with user interaction, so an attacker must reach the service and induce the request; the bounded impact is interruption of the CGI program rather than stated data disclosure or code execution.

CVSS severity3.5
Low
EPSS probability1.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Null pointer dereference in Trend Micro Apex One 2019 and Worry-Free Business Security 10.0 SP1 allows attackers to crash the CGI program via crafted requests. The affected CGI handler dereferences a null pointer when processing attacker-controlled input, but public advisories do not identify the exact function or parameter. The vendor rates exploitation as adjacent-network with user interaction, so an attacker must reach the service and induce the request; the bounded impact is interruption of the CGI program rather than stated data disclosure or code execution.

The record

CVE
CVE-2021-23139
Published
Oct 21, 2021
Updated
Aug 3, 2024
Vendor
Trend Micro
Product
Trend Micro Worry-Free Business Security
Classifications
CWE-476, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 21, 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?

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  1. Affected versionversion=10.0 SP1

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Trend Micro · Trend Micro Worry-Free Business Securityversion=10.0 SP1
Trend Micro · Trend Micro Apex Oneversion=2019

Published CVSS scores

3.5Trend MicroCVSS:3.0/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

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.

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No observations available

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

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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