Security readout for executives and security teams
Plain-English summary
This CVE affects Trend Micro endpoint security management products. A logged-in attacker could upload arbitrary files through the management console, potentially compromising confidentiality, integrity, and availability. It is listed in CISA KEV, so exploitation has been observed. The main limiter is that the attacker first needs valid console access.
Executive priority
Treat this as a near-term remediation item for any affected Trend Micro management server. Active exploitation evidence raises urgency, but the required console login makes access control and credential review central to risk reduction.
Technical view
CVE-2021-36741 is CWE-434 improper input validation enabling arbitrary file upload in Trend Micro Apex One 2019/SaaS, OfficeScan XG SP1, and Worry-Free Business Security 10.0 SP1. CVSS 3.1 is 8.8: network reachable, low complexity, low privileges, no user interaction, high CIA impact.
Likely exposure
Organizations using the listed Trend Micro management products are most exposed, especially where the management console is reachable by broad internal networks, externally exposed, or accessible through compromised administrator accounts. Evidence in the bundle does not define every affected build or fixed version.
Exploitation context
CISA KEV inclusion supports known exploitation. The public description states exploitation requires the attacker to log on to the product management console first. No exploit mechanics, campaign details, or exploitation volume are provided in the supplied sources.
Researcher notes
The source bundle confirms affected product families, CWE-434, CVSS 8.8, and KEV status. It does not provide exploit details, fixed build numbers, or named mitigations. Use Trend Micro advisories to resolve version-specific patch and deployment questions.
Mitigation direction
- Follow Trend Micro advisory guidance for the exact affected product and version.
- Check vendor guidance for fixed builds, hotfixes, or service updates.
- Restrict management console access to trusted administrators and trusted networks.
- Review management console accounts for unnecessary or suspicious access.
- Monitor for unexpected file uploads or product server changes.
Validation and detection
- Inventory Apex One, Apex One as a Service, OfficeScan, and Worry-Free deployments.
- Confirm whether versions match the affected products listed in the CVE record.
- Verify management console exposure and who can authenticate to it.
- Check applied patches or service status against Trend Micro advisories.
- Review logs for unusual console logins and file upload activity.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-434: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-36741 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://success.trendmicro.com/solution/000287819CVE reference · x_refsource_MISC
- https://success.trendmicro.com/solution/000287820CVE reference · x_refsource_MISC
- https://success.trendmicro.com/jp/solution/000287796CVE reference · x_refsource_MISC
- https://success.trendmicro.com/jp/solution/000287815CVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36741CVE reference · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Unrestricted Upload of File with Dangerous Type
Unrestricted Upload of File with Dangerous Type represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.