CVE-2021-1402

HIGHNVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

Score 8.6 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 8.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.6EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.4%CVSS: 8.6Exploit: None knownExposed services: Not assessed

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

A vulnerability in the software-based SSL/TLS message handler of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message through an affected device. SSL/TLS messages sent to an affected device do not trigger this vulnerability. A successful exploit could allow the attacker to cause a process to crash. This crash would then trigger a reload of the device. No manual intervention is needed to recover the device after the reload.

CVSS v3
8.6
EG Score
8.6HIGHmedium confidence
EG Risk
54
EG Risk 54/100CISA SSVC

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
Severity86% × 45%
Exploitation1% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
1.4%
EPSS %ILE
71st
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

April 29, 2021

Last Modified

August 11, 2026

Advisory Details (1)

Auto-updated Aug 11, 2026
No patch confirmed yet.
generic

Cisco Firepower Threat Defense Software SSL Decryption Policy Denial of Service Vulnerability

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-ssl-decrypt-dos-DdyLuK6c

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 32× 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 173 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2021-1402?
CVE-2021-1402 is a high vulnerability published on April 29, 2021. A vulnerability in the software-based SSL/TLS message handler of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient…
When was CVE-2021-1402 disclosed?
CVE-2021-1402 was first published on April 29, 2021, with the most recent update on August 11, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-1402 actively exploited?
CVE-2021-1402 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.4% probability of exploitation in the next 30 days (71st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-1402?
CVE-2021-1402 has a CVSS v3 base score of 8.6 (NVD).
How do I remediate CVE-2021-1402?
No fix for CVE-2021-1402 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix.

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