CVE-2026-20009Network attack vector

Unauthenticated SSH access via incomplete private-key validation

Published Mar 4, 2026 · Updated Mar 4, 2026

Authentication bypass in Cisco Secure Firewall ASA Software allows remote attackers to access SSH as a configured user without the private key. The proprietary Cisco SSH stack insufficiently validates crafted authentication input, allowing the exchange to complete without proof from the user's private key. Exposure requires the Cisco SSH stack, public-key authentication, an interface permitting SSH, and a valid username plus its public key; access is limited to that user's commands and does not grant root.

CVSS severity5.3
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Authentication bypass in Cisco Secure Firewall ASA Software allows remote attackers to access SSH as a configured user without the private key. The proprietary Cisco SSH stack insufficiently validates crafted authentication input, allowing the exchange to complete without proof from the user's private key. Exposure requires the Cisco SSH stack, public-key authentication, an interface permitting SSH, and a valid username plus its public key; access is limited to that user's commands and does not grant root.

The record

CVE
CVE-2026-20009
Published
Mar 4, 2026
Updated
Mar 4, 2026
Vendor
ClamAV
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-138, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=9.17.1
  2. Affected versionversion=9.17.1.10
  3. Affected versionversion=9.17.1.11
  4. Affected versionversion=9.17.1.13
  5. Affected versionversion=9.17.1.15
  6. Affected versionversion=9.17.1.20
  7. Affected versionversion=9.17.1.30
  8. Affected versionversion=9.17.1.33
  9. Affected versionversion=9.17.1.39
  10. Affected versionversion=9.17.1.45
  11. Affected versionversion=9.17.1.46
  12. Affected versionversion=9.17.1.7
  13. Affected versionversion=9.17.1.9
  14. Affected versionversion=9.18.1
  15. Affected versionversion=9.18.1.3
  16. Affected versionversion=9.18.2
  17. Affected versionversion=9.18.2.5
  18. Affected versionversion=9.18.2.7
  19. Affected versionversion=9.18.2.8
  20. Affected versionversion=9.18.3
  21. Affected versionversion=9.18.3.39
  22. Affected versionversion=9.18.3.46
  23. Affected versionversion=9.18.3.53
  24. Affected versionversion=9.18.3.55
  25. Affected versionversion=9.18.3.56
  26. Affected versionversion=9.18.4
  27. Affected versionversion=9.18.4.22
  28. Affected versionversion=9.18.4.24
  29. Affected versionversion=9.18.4.29
  30. Affected versionversion=9.18.4.34
  31. Affected versionversion=9.18.4.40
  32. Affected versionversion=9.18.4.47
  33. Affected versionversion=9.18.4.5
  34. Affected versionversion=9.18.4.50
  35. Affected versionversion=9.18.4.52
  36. Affected versionversion=9.18.4.53
  37. Affected versionversion=9.18.4.57
  38. Affected versionversion=9.18.4.66
  39. Affected versionversion=9.18.4.67
  40. Affected versionversion=9.18.4.68
  41. Affected versionversion=9.18.4.8
  42. Affected versionversion=9.19.1
  43. Affected versionversion=9.19.1.12
  44. Affected versionversion=9.19.1.18
  45. Affected versionversion=9.19.1.22
  46. Affected versionversion=9.19.1.24
  47. Affected versionversion=9.19.1.27
  48. Affected versionversion=9.19.1.28
  49. Affected versionversion=9.19.1.31
  50. Affected versionversion=9.19.1.37
  51. Affected versionversion=9.19.1.38
  52. Affected versionversion=9.19.1.42
  53. Affected versionversion=9.19.1.5
  54. Affected versionversion=9.19.1.9
  55. Affected versionversion=9.20.1
  56. Affected versionversion=9.20.1.5
  57. Affected versionversion=9.20.2
  58. Affected versionversion=9.20.2.10
  59. Affected versionversion=9.20.2.21
  60. Affected versionversion=9.20.2.22
  61. Affected versionversion=9.20.3
  62. Affected versionversion=9.20.3.10
  63. Affected versionversion=9.20.3.13
  64. Affected versionversion=9.20.3.16
  65. Affected versionversion=9.20.3.20
  66. Affected versionversion=9.20.3.4
  67. Affected versionversion=9.20.3.7
  68. Affected versionversion=9.20.3.9
  69. Affected versionversion=9.20.4
  70. Affected versionversion=9.20.4.7
  71. Affected versionversion=9.22.1.1
  72. Affected versionversion=9.22.1.2
  73. Affected versionversion=9.22.1.3
  74. Affected versionversion=9.22.1.6
  75. Affected versionversion=9.22.2
  76. Affected versionversion=9.22.2.13
  77. Affected versionversion=9.22.2.4
  78. Affected versionversion=9.22.2.9
  79. Affected versionversion=9.23.1
  80. Affected versionversion=9.23.1.13
  81. Affected versionversion=9.23.1.3
  82. Affected versionversion=9.23.1.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Adaptive Security Appliance (ASA) Softwareversion=9.17.1; version=9.17.1.10; version=9.17.1.11; version=9.17.1.13; version=9.17.1.15; version=9.17.1.20; version=9.17.1.30; version=9.17.1.33; version=9.17.1.39; version=9.17.1.45; version=9.17.1.46; version=9.17.1.7; version=9.17.1.9; version=9.18.1; version=9.18.1.3; version=9.18.2; version=9.18.2.5; version=9.18.2.7; version=9.18.2.8; version=9.18.3; version=9.18.3.39; version=9.18.3.46; version=9.18.3.53; version=9.18.3.55; version=9.18.3.56; version=9.18.4; version=9.18.4.22; version=9.18.4.24; version=9.18.4.29; version=9.18.4.34; version=9.18.4.40; version=9.18.4.47; version=9.18.4.5; version=9.18.4.50; version=9.18.4.52; version=9.18.4.53; version=9.18.4.57; version=9.18.4.66; version=9.18.4.67; version=9.18.4.68; version=9.18.4.8; version=9.19.1; version=9.19.1.12; version=9.19.1.18; version=9.19.1.22; version=9.19.1.24; version=9.19.1.27; version=9.19.1.28; version=9.19.1.31; version=9.19.1.37; version=9.19.1.38; version=9.19.1.42; version=9.19.1.5; version=9.19.1.9; version=9.20.1; version=9.20.1.5; version=9.20.2; version=9.20.2.10; version=9.20.2.21; version=9.20.2.22; version=9.20.3; version=9.20.3.10; version=9.20.3.13; version=9.20.3.16; version=9.20.3.20; version=9.20.3.4; version=9.20.3.7; version=9.20.3.9; version=9.20.4; version=9.20.4.7; version=9.22.1.1; version=9.22.1.2; version=9.22.1.3; version=9.22.1.6; version=9.22.2; version=9.22.2.13; version=9.22.2.4; version=9.22.2.9; version=9.23.1; version=9.23.1.13; version=9.23.1.3; version=9.23.1.7

Published CVSS scores

5.3Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:X/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-138Improper Neutralization of Special Elements
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo