CVE-2021-27104

CRITICALNVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score elevated to 9.8 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 9.8 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
9.8
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS: 56%CVSS: 9.8Exploit: NoneExposed: 0

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

Accellion FTA 9_12_370 and earlier is affected by OS command execution via a crafted POST request to various admin endpoints. The fixed version is FTA_9_12_380 and later.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
84(Attend)
EG Risk 84/100SSVC: 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
Severity98% × 45%
Exploitation100% × 40%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS
99.0%
KEV
⚠ Exploited

Published

February 16, 2021

Last Modified

November 3, 2025

Advisory Details (1)

Auto-updated Jun 1, 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-2021-27104

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 51× in last 7d / 233× 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 451 total refreshes for this CVE.

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

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Frequently asked(6)

What is CVE-2021-27104?
CVE-2021-27104 is a critical vulnerability published on February 16, 2021. Accellion FTA 912370 and earlier is affected by OS command execution via a crafted POST request to various admin endpoints. The fixed version is FTA912_380 and later.
When was CVE-2021-27104 disclosed?
CVE-2021-27104 was first published in the National Vulnerability Database on February 16, 2021, with the most recent update on November 3, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-27104 actively exploited?
Yes. CISA added CVE-2021-27104 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Accellion FTA. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-27104?
CVE-2021-27104 has a CVSS v3 base score of 9.8 (NVD).
Which products are affected by CVE-2021-27104?
CVE-2021-27104 affects Accellion FTA. 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-2021-27104?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-27104, 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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