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
91%
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 41× in last 7d / 220× 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 465 total refreshes for this CVE.

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

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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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