CVE-2021-36742
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 the ability to execute low-privileged code on the target system in order to exploit this vulnerability.
- CVSS
- 7.8Highscored by CISA
- Exploited in the wild
- Yes, in CISA KEV since 3 Nov 2021CISA deadline for US federal agencies: 17 Nov 2021
- EPSS
- 1.5%chance of exploitation in the next 30 daystop 26% of scored CVEsFIRST score of 11 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 29 Jul 2021analysed here 12 Nov 2026
Do first. Apply updates per vendor instructions. (CISA's required action for this KEV entry)
Summary
Triage
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
| Product | Affected versions | Vendor says fixed in |
|---|---|---|
| Trend Micro Trend Micro Apex One | 2019, SaaSVendor says fixed in: not stated | |
| Trend Micro Trend Micro OfficeScan | XG SP1Vendor says fixed in: not stated | |
| Trend Micro Trend Micro Worry-Free Business Security | 10.0 SP1Vendor says fixed in: not stated |
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
Products named in our analysis
- trendmicro:officescan
- trendmicro:officescan_business_security
- trendmicro:apex_one
- trendmicro:worry-free_business_security
Fix and mitigation
WAF and other mitigations
Can a WAF block it? No. The attack needs local access to the machine, so a WAF is not on its path.
Also consider: patch
Based on the attack vector (local or physical access). We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Listed since 3 Nov 2021.
- CISA due date
- 17 Nov 2021, the remediation deadline for US federal agencies
- CISA required action
- Apply updates per vendor instructions.
- Public exploit code
- None on record in Exploit-DB, Metasploit, Nuclei templates or PoC-in-GitHub.
- CISA SSVC
- exploitation active, automatable no, technical impact totalAssessed by CISA 6 Feb 2025 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
Timeline
- 29 Jul 2021Published
- 3 Nov 2021Added to CISA KEV (exploited in the wild)96 days (about 3 months) later
- 17 Nov 2021CISA remediation due date (US federal agencies)14 days later
- 6 Feb 2025CISA SSVC assessment: exploitation active1,178 days (about 3 years) later
- 21 Oct 2025CVE record last updated257 days (about 9 months) later
- 12 Nov 2026Analysed by vulneraibility.com387 days (about 1 year) later
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
| Metric | Value | What it means |
|---|---|---|
| Attack vector | LocalLocal access required (shell, logged-in user). | Local access required (shell, logged-in user). |
| Attack complexity | LowRepeatable attack, no special conditions. | Repeatable attack, no special conditions. |
| Privileges required | LowThe attacker needs basic user privileges. | The attacker needs basic user privileges. |
| User interaction | NoneNo victim action needed. | No victim action needed. |
| Scope | UnchangedImpact stays within the vulnerable component. | Impact stays within the vulnerable component. |
| Confidentiality | HighTotal data disclosure possible. | Total data disclosure possible. |
| Integrity | HighComplete modification possible. | Complete modification possible. |
| Availability | HighFull outage possible. | Full outage possible. |
Common questions
Is CVE-2021-36742 being exploited?
Yes. CVE-2021-36742 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2021-36742?
CVE-2021-36742 is rated High with a CVSS score of 7.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2021-36742?
Yes. A fix has been recorded for CVE-2021-36742. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2021-36742 affect?
CVE-2021-36742 affects trendmicro:officescan, trendmicro:officescan_business_security, trendmicro:apex_one, trendmicro:worry-free_business_security. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
5 references in the CVE record, grouped by the tags the record gives them.
Other links (5)
- success.trendmicro.com /solution/000287819
- success.trendmicro.com /solution/000287820
- success.trendmicro.com /jp/solution/000287796
- success.trendmicro.com /jp/solution/000287815
- cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36742
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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