Cyber Resilience

CVE-2021-36741

Trendmicro Officescan xg

CISA KEVActive ExploitationEUVD Exploited
Published
29 July 2021
Modified
31 October 2025
KEV Added
03 November 2021
Patch / advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.050 91th percentile
Risk Priority 90 floored blend · peak EPSS

Summary

CVE-2021-36741 is a high-severity Unrestricted Upload of File with Dangerous Type (CWE-434) vulnerability in Trendmicro Officescan. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 9% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2021-36741 is an improper input validation vulnerability, categorized under CWE-434, that affects Trend Micro Apex One, Apex One as a Service, OfficeScan XG, and Worry-Free Business Security 10.0 SP1. It permits remote attackers to upload arbitrary files to affected installations, with a CVSS 3.1 base score of 8.8 reflecting high impact on confidentiality, integrity, and availability over a network vector.

An attacker who has already obtained valid credentials to log on to the product's management console can exploit the flaw to upload malicious files, potentially leading to code execution or further compromise of the system.

Advisories and solution documents addressing the issue are published by the vendor at https://success.trendmicro.com/jp/solution/000287796, https://success.trendmicro.com/jp/solution/000287815, https://success.trendmicro.com/solution/000287819, https://success.trendmicro.com/solution/000287820, and https://success.trendmicro.com/jp/solution/000287796. No information on observed in-the-wild exploitation is provided in the available references.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

obtain the ability to logon to the product�s management console in order to exploit this vulnerability.

CWE(s)
KEV Date Added
03 November 2021

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1505 Server Software Component Persistence
Adversaries may abuse legitimate extensible development features of servers to establish persistent access to systems.
T1505.003 Web Shell Persistence
Adversaries may backdoor web servers with web shells to establish persistent access to systems.
T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
T1105 Ingress Tool Transfer Command And Control
Adversaries may transfer tools or other files from an external system into a compromised environment.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2021-36742Same product: Microsoft Windowsboth on KEV
CVE-2021-31207Same vendor: Microsoftboth on KEV
CVE-2020-24557Same product: Microsoft Windowsboth on KEV
CVE-2021-26828Same product: Microsoft Windowsboth on KEV
CVE-2023-41179Same product: Microsoft Windowsboth on KEV
CVE-2021-20022Same product: Microsoft Windowsboth on KEV
CVE-2019-18187Same product: Microsoft Windowsboth on KEV
CVE-2017-12615Same product: Microsoft Windowsboth on KEV
CVE-2025-47866Same product: Microsoft Windows
CVE-2022-40139Same product: Microsoft Windowsboth on KEV

Affected Assets

trendmicro
officescan
xg
trendmicro
officescan business security
10.0
trendmicro
apex one
2019
trendmicro
worry-free business security
10.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V5.1.1

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-434

Requiring identifiable owners for portable devices reduces the attack surface for unrestricted uploads of dangerous file types via anonymous media.

addresses: CWE-434

Dangerous file uploads can be detonated in the chamber to determine malice before any production write or execution occurs.

addresses: CWE-434

Prevents unrestricted writing of arbitrary or malicious firmware by keeping hardware write-protect enabled except under tightly controlled manual procedures.

addresses: CWE-434

Scans files from external sources on download/open/execute, blocking unrestricted uploads of dangerous file types.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-05 mostly match
prevents

Restricting execution of unauthorized software directly blocks dangerous uploaded files from running.

PR.PS-01 partial match
prevents

Hardened configuration baselines can enforce allowed file types and processing rules.

PR.PS-06 partial match
prevents

Secure development practices include input validation and file-type restrictions that prevent this weakness.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Configuration and acceptance testing verify that file-upload handling enforces allowed types and does not permit dangerous content to be stored or executed.

prevents

Secure-coding guidelines and security testing explicitly address restrictions on allowed file types and upload handling, reducing the risk that dangerous file uploads are accepted without validation.

prevents

Mandated testing for malicious content and known vulnerabilities reduces the likelihood that an outsourced component will contain or accept dangerous file types that could later be uploaded or executed.

mitigates

Application allow-listing and pre-use scanning of received files directly blocks the introduction of executable content that has not been vetted, eliminating the primary vector for unrestricted dangerous file uploads.

References