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UK Cyber Defence
VulnerabilityAnalyzed

CVE-2021-36741

Trend Micro Multiple Products Improper Input Validation Vulnerability

KEVHIGH 8.8EPSS 4.95%

Does this matter?

Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 November 2021). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.

Description

An 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 remote attached to upload arbitrary files on affected installations. Please note: an attacker must first obtain the ability to logon to the product�s management console in order to exploit this vulnerability.

CVSS 3.1
8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS
4.95% probability · 92th percentile
Public exploits
None in Exploit-DB
CISA KEV
Listed 3 November 2021 · due 17 November 2021
Weakness
CWE-434
Affected
trendmicro/officescan · trendmicro/officescan business security · trendmicro/apex one · trendmicro/worry-free business security
Source
security@trendmicro.com
EPSS trend
0%3%5%30 October 2026: 4.95%30 October 202630 October 2026

EPSS 5.0% since 30 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

CISA notes

Apply updates per vendor instructions. https://success.trendmicro.com/dcx/s/solution/000287819?language=en_US, https://success.trendmicro.com/dcx/s/solution/000287820?language=en_US; https://nvd.nist.gov/vuln/detail/CVE-2021-36741

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.