Threats / Trend Micro / CVE-2021-36741
CVE-2021-36741
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Trend Micro Apex One, One as a Service, and Worry-Free Busin vulnerability
Trend Micro Apex One, Apex One as a Service, and Worry-Free Business Security contain an improper input validation vulnerability allowing remote file upload.
Verdict
Today item — known-exploited.
A remote attacker can exploit improper input validation to upload arbitrary files to affected Trend Micro security products. This vulnerability has been observed in active exploitation and enables potential code execution or system compromise.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
2 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03).
Probability (EPSS)
EPSS 0.04951 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Trend Micro, Apex One, Apex One as a Service, and Worry-Free Business Security. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-22 Path Traversal — weakness family: Path traversal / file.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I identify that the security product lacks proper file upload validation controls.
Business
Security product becomes an attack vector rather than a protective layer.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I craft and submit a malicious file that bypasses input validation checks.
Business
Malicious payload reaches the protected system undetected by the security solution.
3
Lateral reach — past segmentation narrative 3
Attacker
I achieve code execution or persistence through the uploaded file.
Business
Endpoint or server is compromised, potentially affecting business operations and data security.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05
Coverage & confidence
— what we know, and what we don’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by trendmicroCNA
Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.