How severe is CVE-2021-23139?

CVE-2021-23139 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-23139 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-23139?

CVE-2021-23139 primarily affects Trendmicro Apex One. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-23139?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-23139 published?

CVE-2021-23139 was published on 2021-10-21 and last updated on 2026-06-17.

CVE-2021-23139

CVE-2021-23139 is a high-severity vulnerability in Trendmicro Apex One with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (61st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Trendmicro Apex One
Published: 2021-10-21
Last modified: 2026-06-17

Description

A null pointer vulnerability in Trend Micro Apex One and Worry-Free Business Security 10.0 SP1 could allow an attacker to crash the CGI program on affected installations.

Frequently asked questions

What is CVE-2021-23139?: A null pointer vulnerability in Trend Micro Apex One and Worry-Free Business Security 10.0 SP1 could allow an attacker to crash the CGI program on affected installations.
How severe is CVE-2021-23139?: CVE-2021-23139 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-23139 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-23139?: CVE-2021-23139 primarily affects Trendmicro Apex One. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-23139?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-23139 published?: CVE-2021-23139 was published on 2021-10-21 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:trendmicro:apex_one:2019:*:*:*:*:*:*:*
cpe:2.3:a:trendmicro:apex_one:2019:*:*:*:saas:*:*:*
cpe:2.3:a:trendmicro:worry-free_business_security:10.0:sp1:*:*:*:*:*:*
cpe:2.3:a:trendmicro:worry-free_business_security_services:-:*:*:*:saas:*:*:*

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