CVE-2021-36741

CRITICALNVD 8.89.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 8.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 4 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 5%CVSS: 8.8Exploit: cisa kev · ssvc activeExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

CVSS v3
8.8
EG Score
9.0(high)
EG Risk
81(Attend)
EG Risk 81/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation100% × 40%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
5%
EPSS %ILE
92%
KEV
⚠ Exploited

Published

July 29, 2021

Last Modified

October 31, 2025

Advisory Details (3)

Auto-updated Jun 2, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36741
generic

Article unavailable

https://success.trendmicro.com/solution/000287820
generic

Article unavailable

https://success.trendmicro.com/solution/000287819

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 60× in last 7d / 253× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 923 total refreshes for this CVE.

  1. 2026-09-20 17:56 UTCGHSA enrichment
  2. 2026-09-20 13:53 UTCGHSA enrichment
  3. 2026-09-20 09:51 UTCGHSA enrichment
  4. 2026-09-20 05:49 UTCGHSA enrichment
  5. 2026-09-20 01:47 UTCGHSA enrichment
  6. 2026-09-19 21:45 UTCGHSA enrichment
  7. 2026-09-19 17:43 UTCEG score recompute
  8. 2026-09-19 17:43 UTCGHSA enrichment
  9. 2026-09-19 15:38 UTCEPSS rescore
  10. 2026-09-19 13:41 UTCGHSA enrichment
  11. 2026-09-19 09:38 UTCGHSA enrichment
  12. 2026-09-19 05:32 UTCGHSA enrichment
  13. 2026-09-19 01:30 UTCGHSA enrichment
  14. 2026-09-18 21:28 UTCEG score recompute
  15. 2026-09-18 21:28 UTCGHSA enrichment
  16. 2026-09-18 19:23 UTCEPSS rescore
  17. 2026-09-18 19:20 UTCCISA KEV update
  18. 2026-09-18 17:25 UTCGHSA enrichment
  19. 2026-09-18 14:15 UTCCISA KEV update
  20. 2026-09-18 13:23 UTCGHSA enrichment
  21. 2026-09-18 09:20 UTCGHSA enrichment
  22. 2026-09-18 05:18 UTCGHSA enrichment
  23. 2026-09-18 01:16 UTCGHSA enrichment
  24. 2026-09-17 21:14 UTCEG score recompute
  25. 2026-09-17 21:14 UTCGHSA enrichment
Show 75 more
  1. 2026-09-17 19:23 UTCEPSS rescore
  2. 2026-09-17 19:23 UTCEPSS rescore
  3. 2026-09-17 17:11 UTCGHSA enrichment
  4. 2026-09-17 13:06 UTCGHSA enrichment
  5. 2026-09-17 09:03 UTCGHSA enrichment
  6. 2026-09-17 05:01 UTCGHSA enrichment
  7. 2026-09-17 00:59 UTCGHSA enrichment
  8. 2026-09-16 20:55 UTCGHSA enrichment
  9. 2026-09-16 16:51 UTCEG score recompute
  10. 2026-09-16 16:51 UTCGHSA enrichment
  11. 2026-09-16 14:10 UTCCISA KEV update
  12. 2026-09-16 14:05 UTCEPSS rescore
  13. 2026-09-16 14:05 UTCEPSS rescore
  14. 2026-09-16 12:47 UTCGHSA enrichment
  15. 2026-09-16 08:45 UTCEG score recompute
  16. 2026-09-16 08:45 UTCGHSA enrichment
  17. 2026-09-16 04:42 UTCGHSA enrichment
  18. 2026-09-16 00:40 UTCGHSA enrichment
  19. 2026-09-15 20:37 UTCGHSA enrichment
  20. 2026-09-15 16:30 UTCGHSA enrichment
  21. 2026-09-15 12:27 UTCGHSA enrichment
  22. 2026-09-15 08:25 UTCGHSA enrichment
  23. 2026-09-15 04:23 UTCEG score recompute
  24. 2026-09-15 04:23 UTCGHSA enrichment
  25. 2026-09-15 03:06 UTCEPSS rescore
  26. 2026-09-15 00:20 UTCGHSA enrichment
  27. 2026-09-14 20:18 UTCGHSA enrichment
  28. 2026-09-14 19:24 UTCCISA KEV update
  29. 2026-09-14 16:16 UTCGHSA enrichment
  30. 2026-09-14 12:13 UTCGHSA enrichment
  31. 2026-09-14 08:11 UTCGHSA enrichment
  32. 2026-09-14 04:09 UTCGHSA enrichment
  33. 2026-09-14 00:06 UTCGHSA enrichment
  34. 2026-09-13 20:03 UTCEG score recompute
  35. 2026-09-13 20:03 UTCGHSA enrichment
  36. 2026-09-13 16:43 UTCEPSS rescore
  37. 2026-09-13 16:01 UTCGHSA enrichment
  38. 2026-09-13 11:59 UTCGHSA enrichment
  39. 2026-09-13 07:56 UTCGHSA enrichment
  40. 2026-09-13 03:54 UTCGHSA enrichment
  41. 2026-09-12 23:52 UTCGHSA enrichment
  42. 2026-09-12 19:50 UTCGHSA enrichment
  43. 2026-09-12 15:48 UTCEG score recompute
  44. 2026-09-12 15:48 UTCGHSA enrichment
  45. 2026-09-12 14:57 UTCEPSS rescore
  46. 2026-09-12 11:45 UTCGHSA enrichment
  47. 2026-09-12 07:42 UTCGHSA enrichment
  48. 2026-09-12 03:39 UTCGHSA enrichment
  49. 2026-09-11 23:37 UTCGHSA enrichment
  50. 2026-09-11 19:35 UTCGHSA enrichment
  51. 2026-09-11 18:49 UTCCISA KEV update
  52. 2026-09-11 15:33 UTCEG score recompute
  53. 2026-09-11 15:33 UTCGHSA enrichment
  54. 2026-09-11 14:49 UTCEPSS rescore
  55. 2026-09-11 11:30 UTCEG score recompute
  56. 2026-09-11 11:30 UTCGHSA enrichment
  57. 2026-09-11 09:33 UTCEPSS rescore
  58. 2026-09-11 07:22 UTCGHSA enrichment
  59. 2026-09-11 03:20 UTCGHSA enrichment
  60. 2026-09-10 23:17 UTCGHSA enrichment
  61. 2026-09-10 19:28 UTCCISA KEV update
  62. 2026-09-10 19:15 UTCGHSA enrichment
  63. 2026-09-10 15:13 UTCGHSA enrichment
  64. 2026-09-10 11:10 UTCEG score recompute
  65. 2026-09-10 11:10 UTCGHSA enrichment
  66. 2026-09-10 07:04 UTCGHSA enrichment
  67. 2026-09-10 03:02 UTCGHSA enrichment
  68. 2026-09-09 23:00 UTCGHSA enrichment
  69. 2026-09-09 19:08 UTCCISA KEV update
  70. 2026-09-09 18:58 UTCGHSA enrichment
  71. 2026-09-09 14:55 UTCGHSA enrichment
  72. 2026-09-09 10:52 UTCGHSA enrichment
  73. 2026-09-09 06:49 UTCGHSA enrichment
  74. 2026-09-09 02:47 UTCGHSA enrichment
  75. 2026-09-08 22:45 UTCEG score recompute

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Frequently asked(6)

What is CVE-2021-36741?
CVE-2021-36741 is a critical vulnerability published on July 29, 2021. 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 obtain the ability to logon to the…
When was CVE-2021-36741 disclosed?
CVE-2021-36741 was first published in the National Vulnerability Database on July 29, 2021, with the most recent update on October 31, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-36741 actively exploited?
Yes. CISA added CVE-2021-36741 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Trend Micro Apex One, Apex One as a Service, and Worry-Free Business Security. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-36741?
CVE-2021-36741 has a CVSS v3 base score of 8.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2021-36741?
CVE-2021-36741 affects Trend Micro Apex One, Apex One as a Service, and Worry-Free Business Security. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2021-36741?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-36741, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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