CVE-2026-20103Network attack vector

Remote VPN service interruption via unchecked packet input

Published Mar 4, 2026 · Updated Mar 4, 2026

Memory exhaustion in Cisco ASA and Secure FTD Remote Access SSL VPN allows remote attackers to interrupt new VPN connections. The VPN server accepts crafted packets without validating attacker-controlled input and continues allocating memory until resources are exhausted. Remote Access SSL VPN must be enabled; no authentication is required, and the management interface can become temporarily unresponsive.

CVSS severity8.6
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory exhaustion in Cisco ASA and Secure FTD Remote Access SSL VPN allows remote attackers to interrupt new VPN connections. The VPN server accepts crafted packets without validating attacker-controlled input and continues allocating memory until resources are exhausted. Remote Access SSL VPN must be enabled; no authentication is required, and the management interface can become temporarily unresponsive.

The record

CVE
CVE-2026-20103
Published
Mar 4, 2026
Updated
Mar 4, 2026
Vendor
ClamAV
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-770, T1499.004
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=9.12.4.48
  2. Affected versionversion=9.12.4.50
  3. Affected versionversion=9.12.4.52
  4. Affected versionversion=9.12.4.54
  5. Affected versionversion=9.12.4.55
  6. Affected versionversion=9.12.4.56
  7. Affected versionversion=9.12.4.58
  8. Affected versionversion=9.12.4.62
  9. Affected versionversion=9.12.4.65
  10. Affected versionversion=9.12.4.67
  11. Affected versionversion=9.16.3.15
  12. Affected versionversion=9.16.3.19
  13. Affected versionversion=9.16.3.23
  14. Affected versionversion=9.16.4
  15. Affected versionversion=9.16.4.14
  16. Affected versionversion=9.16.4.19
  17. Affected versionversion=9.16.4.27
  18. Affected versionversion=9.16.4.38
  19. Affected versionversion=9.16.4.39
  20. Affected versionversion=9.16.4.42
  21. Affected versionversion=9.16.4.48
  22. Affected versionversion=9.16.4.55
  23. Affected versionversion=9.16.4.57
  24. Affected versionversion=9.16.4.61
  25. Affected versionversion=9.16.4.62
  26. Affected versionversion=9.16.4.67
  27. Affected versionversion=9.16.4.70
  28. Affected versionversion=9.16.4.71
  29. Affected versionversion=9.16.4.76
  30. Affected versionversion=9.16.4.82
  31. Affected versionversion=9.16.4.84
  32. Affected versionversion=9.16.4.9
  33. Affected versionversion=9.17.1.20
  34. Affected versionversion=9.17.1.30
  35. Affected versionversion=9.17.1.33
  36. Affected versionversion=9.17.1.39
  37. Affected versionversion=9.17.1.45
  38. Affected versionversion=9.17.1.46
  39. Affected versionversion=9.18.1.3
  40. Affected versionversion=9.18.2
  41. Affected versionversion=9.18.2.5
  42. Affected versionversion=9.18.2.7
  43. Affected versionversion=9.18.2.8
  44. Affected versionversion=9.18.3
  45. Affected versionversion=9.18.3.39
  46. Affected versionversion=9.18.3.46
  47. Affected versionversion=9.18.3.53
  48. Affected versionversion=9.18.3.55
  49. Affected versionversion=9.18.3.56
  50. Affected versionversion=9.18.4
  51. Affected versionversion=9.18.4.22
  52. Affected versionversion=9.18.4.24
  53. Affected versionversion=9.18.4.29
  54. Affected versionversion=9.18.4.34
  55. Affected versionversion=9.18.4.40
  56. Affected versionversion=9.18.4.47
  57. Affected versionversion=9.18.4.5
  58. Affected versionversion=9.18.4.50
  59. Affected versionversion=9.18.4.52
  60. Affected versionversion=9.18.4.53
  61. Affected versionversion=9.18.4.57
  62. Affected versionversion=9.18.4.8
  63. Affected versionversion=9.19.1
  64. Affected versionversion=9.19.1.12
  65. Affected versionversion=9.19.1.18
  66. Affected versionversion=9.19.1.22
  67. Affected versionversion=9.19.1.24
  68. Affected versionversion=9.19.1.27
  69. Affected versionversion=9.19.1.28
  70. Affected versionversion=9.19.1.31
  71. Affected versionversion=9.19.1.37
  72. Affected versionversion=9.19.1.38
  73. Affected versionversion=9.19.1.42
  74. Affected versionversion=9.19.1.5
  75. Affected versionversion=9.19.1.9
  76. Affected versionversion=9.20.1
  77. Affected versionversion=9.20.1.5
  78. Affected versionversion=9.20.2
  79. Affected versionversion=9.20.2.10
  80. Affected versionversion=9.20.2.21
  81. Affected versionversion=9.20.2.22
  82. Affected versionversion=9.20.3
  83. Affected versionversion=9.20.3.10
  84. Affected versionversion=9.20.3.13
  85. Affected versionversion=9.20.3.16
  86. Affected versionversion=9.20.3.20
  87. Affected versionversion=9.20.3.4
  88. Affected versionversion=9.20.3.7
  89. Affected versionversion=9.20.3.9
  90. Affected versionversion=9.22.1.1
  91. Affected versionversion=9.22.1.2
  92. Affected versionversion=9.22.1.3
  93. Affected versionversion=9.22.1.6
  94. Affected versionversion=9.22.2
  95. Affected versionversion=9.22.2.4
  96. Affected versionversion=9.23.1
  97. Affected versionversion=9.23.1.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Adaptive Security Appliance (ASA) Softwareversion=9.12.4.48; version=9.12.4.50; version=9.12.4.52; version=9.12.4.54; version=9.12.4.55; version=9.12.4.56; version=9.12.4.58; version=9.12.4.62; version=9.12.4.65; version=9.12.4.67; version=9.16.3.15; version=9.16.3.19; version=9.16.3.23; version=9.16.4; version=9.16.4.14; version=9.16.4.19; version=9.16.4.27; version=9.16.4.38; version=9.16.4.39; version=9.16.4.42; version=9.16.4.48; version=9.16.4.55; version=9.16.4.57; version=9.16.4.61; version=9.16.4.62; version=9.16.4.67; version=9.16.4.70; version=9.16.4.71; version=9.16.4.76; version=9.16.4.82; version=9.16.4.84; version=9.16.4.9; 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=9.18.1.3; 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=9.18.4.8; 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=9.22.1.1; version=9.22.1.2; version=9.22.1.3; version=9.22.1.6; version=9.22.2; version=9.22.2.4; version=9.23.1; version=9.23.1.3
ClamAV · Cisco Secure Firewall Threat Defenseversion=6.4.0.16; version=6.4.0.17; version=6.4.0.18; version=7.0.4; version=7.0.5; version=7.0.6; version=7.0.6.1; version=7.0.6.2; version=7.0.6.3; version=7.0.7; version=7.0.8; version=7.0.8.1; version=7.1.0.3; version=7.2.1; version=7.2.10; version=7.2.10.2; version=7.2.2; version=7.2.3; version=7.2.4; version=7.2.4.1; version=7.2.5; version=7.2.5.1; version=7.2.5.2; version=7.2.6; version=7.2.7; version=7.2.8; version=7.2.8.1; version=7.2.9; version=7.3.0; version=7.3.1; version=7.3.1.1; version=7.3.1.2; version=7.4.0; version=7.4.1; version=7.4.1.1; version=7.4.2; version=7.4.2.1; version=7.4.2.2; version=7.4.2.3; version=7.4.2.4; version=7.6.0; version=7.6.1; version=7.6.2; version=7.6.2.1; version=7.7.0; version=7.7.10; version=7.7.10.1

Published CVSS scores

8.6Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Endpoint Denial of Service: Application or System Exploitation

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

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Your stack

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