VulnTideExploited vulnerabilities, by vendor. Data as of 28 Oct 2026.
Known exploitedIn CISA's KEV catalog since 3 November 2021Ransomware use: unknown
Trend Micro Apex One, Apex One as a Service, and Worry-Free Business Security

CVE-2021-36742: Trend Micro Multiple Products Improper Input Validation Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 3 Nov 2021, 97 days after the CVE record was published.

How likely is exploitation in the next 30 days?
1.5%

EPSS score, percentile 73.9 of all scored records

How severe?
7.8 High

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

CISA deadline 17 Nov 2021. Apply updates per vendor instructions.

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

Which versions are affected?

Affected

  • 2019, SaaS
  • XG SP1
  • 10.0 SP1

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

Required action, set by CISA

Apply updates per vendor instructions.

CISA due date for this action: 17 November 2021.

Advisories and patches

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

Linked from CISA's catalog entry

Affected products and versions

As listed in the CVE record.

Trend Micro Trend Micro Apex One
StatusVersions
Affected2019, SaaS
Trend Micro Trend Micro OfficeScan
StatusVersions
AffectedXG SP1
Trend Micro Trend Micro Worry-Free Business Security
StatusVersions
Affected10.0 SP1

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

Trend Micro Apex One, Apex One as a Service, and Worry-Free Business Security contain an improper input validation vulnerability that allows for privilege escalation.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

  • CISA added CVE-2021-36742 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Nov 2021.
  • CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
  • The due date CISA sets for the required action is 17 Nov 2021.
  • The CVE record was published on 29 Jul 2021, 97 days before it was added to KEV.
  • The CVE record carries a CVSS v3.1 base score of 7.8 (High), taken from CISA's enrichment of the record.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 1.5% (percentile 73.9), as of 28 Oct 2026.
  • CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

A improper input validation vulnerability in Trend Micro Apex One, Apex One as a Service, OfficeScan XG and Worry-Free Business Security 10.0 SP1 allows a local attacker to escalate privileges on affected installations. Please note: an attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

  • CWE-20: Improper Input Validation

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

DateEvent
29 Jul 2021CVE record published
3 Nov 2021Added to CISA KEV
17 Nov 2021CISA due date for the required action
21 Oct 2025CVE record last updated

References

More exploited Trend Micro vulnerabilities

  • CVE-2026-34926: Trend Micro Apex One (On-Premise) Directory Traversal Vulnerability (added 21 May 2026)
  • CVE-2025-54948: Trend Micro Apex One OS Command Injection Vulnerability (added 18 Aug 2025)
  • CVE-2023-41179: Trend Micro Apex One and Worry-Free Business Security Remote Code Execution Vulnerability (added 21 Sep 2023)
  • CVE-2022-40139: Trend Micro Apex One and Apex One as a Service Improper Validation Vulnerability (added 15 Sep 2022)
  • CVE-2022-26871: Trend Micro Apex Central Arbitrary File Upload Vulnerability (added 31 Mar 2022)
  • CVE-2019-18187: Trend Micro OfficeScan Directory Traversal Vulnerability (added 3 Nov 2021)