Security Resilience

CVE-2021-36742

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 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.015 73th percentile
Risk Priority 83 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2021-36742 is a high-severity Improper Input Validation (CWE-20) vulnerability in Trendmicro Officescan. Its CVSS base score is 7.8 (High).

Operationally, ranked in the top 27% 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-2021-36742 is an improper input validation vulnerability, tracked under CWE-20, that affects Trend Micro Apex One, Apex One as a Service, OfficeScan XG, and Worry-Free Business Security 10.0 SP1. The flaw permits a local attacker to escalate privileges on affected installations when they already possess the ability to run low-privileged code.

An attacker with an initial low-privileged foothold can exploit the vulnerability to obtain higher privileges, resulting in full control over confidentiality, integrity, and availability of the system as reflected in its CVSS 3.1 base score of 7.8.

Trend Micro has published solution articles addressing the issue for each affected product line; these advisories are available at the vendor's success.trendmicro.com portals and contain the relevant updates and configuration guidance.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

CWE(s)
KEV Date Added
03 November 2021

Related Threats

CVEs Like This One

CVE-2021-36741Same product: Microsoft Windowsboth on KEV
CVE-2020-24557Same product: Microsoft Windowsboth on KEV
CVE-2023-41179Same product: Microsoft Windowsboth on KEV
CVE-2022-40139Same product: Microsoft Windowsboth on KEV
CVE-2019-18187Same product: Microsoft Windowsboth on KEV
CVE-2020-8468Same product: Trendmicro Apex Oneboth on KEV
CVE-2015-2291Same product: Microsoft Windowsboth on KEV
CVE-2019-0604Same vendor: Microsoftboth on KEV
CVE-2025-32706Same vendor: Microsoftboth on KEV
CVE-2020-1350Same vendor: Microsoftboth 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

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-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

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.

blocks

A.8.25 mandates security requirements, secure coding guidelines, checkpoints, testing (incl. code scans) and developer training in the SDLC, which reaches a slice of input validation defects but leaves the majority (incomplete enforcement, second-order inputs, parser differentials, post-validation canonicalization) unaddressed as in the SA-3 and A.8.28 anchors.

blocks

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

blocks

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

prevents

Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-20, a class-level weakness, and none of its children carries one either.

References